BDD to Working Code: Three Synthesis Demos, Given/Then Through to Result
For new readers
Example-Driven Synthesis covers how this engine works: given input→output examples, it searches for the smallest composition of PatLang primitives that reproduces every one exactly, then emits the result as real, runnable source. This page shows three of those demos end to end — the Given/Then examples, the exact PatLang source (unedited, straight from the project's own committed test files), and the result. The first two run live, right here, via the same shared WebAssembly-compiled PatLang compiler every other "compile and run in this browser" card on this site reuses — no server, no rustc.
TheyThey weren't live on this page's first attempt. Building it turned up a real bug: a plain, unmodified gt(a, b) synthesis search that resolves instantly against the native interpreter returned no match at all under the shared in-browser compiler. Traced to the actual cause rather than left as a mystery: host_coerce_arg (rust-runtime/src/ir/codegen.rs), a deliberate migration shim from when PatLang's numeric tower first split a single generic number type into distinct Int/Float variants, flattens every host-function argument back down to a generic number at the call boundary — harmless for a function that reads a number and discards it, but list_push, list_set, and Dict field storage all store their argument for later retrieval, and a value stored this way came back reporting itself as "float" forever after, even for a plain int literal. Since these demos store their example bindings in a Dict, every synthesis search run this way was silently searching over the wrong types. Fixed directly in the runtime (affecting natively-compiled programs too, not just this in-browser path) rather than worked around here. A second, separate gap in the same investigation — parallel_map hard-failing on an ordinary, non-threaded WebAssembly target instead of falling back to running sequentially — also got fixed rather than left as a silent reason for the second demo below to stay static.
Object + events: a bank account, its withdrawal logic derived from five examples
TwoTwo independent pieces are derived here from separate Given/Then example sets: the balance update itself, and a second, separate decision — whether an insufficient_funds event should fire at all. Both feed a real Account object using real when/emit event wiring; only that wiring is hand-written, the two decisions are not.
Given balance = 100, amount = 30 Then result = 70
Given balance = 100, amount = 100 Then result = 0
Given balance = 100, amount = 150 Then result = 100 # can't fulfil: unchanged
Given balance = 50, amount = 20 Then result = 30
Given balance = 50, amount = 60 Then result = 50 # can't fulfil: unchanged
Given balance = 100, amount = 150 Then insufficient = true
Given balance = 100, amount = 70 Then insufficient = false
Given balance = 50, amount = 50 Then insufficient = false # exact boundary
Given balance = 50, amount = 51 Then insufficient = true
Given balance = 30, amount = 10 Then insufficient = false# Object + event combination -- the next complexity tier above synth_
# demo_account_object.patlang and synth_demo_inventory_events.patlang
# separately: an Account object's own withdraw method now composes TWO
# independently-derived pieces (not one), and uses the second one's
# result to decide whether to emit an event at all -- the DECISION of
# "should this fire" is itself synthesized, not hand-written.
#
# apply_withdraw(balance, amount) = amount > balance
# ? balance -- clamp, same as before
# : balance - amount
# is_insufficient(balance, amount) = amount > balance -- gt witness, trivial
#
# withdraw() (hand-authored wiring, the only hand-written code here)
# evaluates BOTH derived ASTs against the same call, updates balance
# from the first, and emits "insufficient_funds" only when the SECOND
# one says so -- a real composition of two synthesized pieces inside
# one stateful method, plus real event delivery out of it, mirroring
# exactly how synth_demo_search_replace.patlang composed find_position
# + splice into replace_in_text, just across the object/event boundary
# instead of within one pure expression.
# ---- Bidirectional (meet-in-the-middle) synthesis via witness
# functions -- Phase 1 of the design at
# C:\Users\p\.claude\plans\yes-design-it-bidirectional-witness.md
# (issue #69's markdown scaling wall).
#
# Every fix tried on #69 so far (windowing, chunked parallelization,
# GOAP translation, fact-cost relaxation) kept the same shape: generate
# every forward combination, THEN check it against the goal. This file
# adds a second, backward direction: at each level, before growing the
# forward pool further, ask "does the GOAL decompose, via some
# invertible primitive, into pieces that already exist in the forward
# index?" -- turning "search until you stumble on the goal" into
# "actively look for a route to it." The meet-in-the-middle check
# itself is just an exact-value scan over the SAME (type,size)-bucketed
# index synthesize_from_examples already builds (sbe_index_lookup) --
# no new index structure, no change to the forward loop it's borrowed
# from.
#
# Phase 1 covers the cleanly-invertible primitives only: concat (split
# the target string at every possible point) and add/sub (classic
# two-sum-style arithmetic inversion, checking only against ALREADY
# forward-built values, never inventing new ones speculatively). cond's
# disjunctive witness (Phase 2: partition examples by which branch must
# have fired, search each branch independently, then search for the
# separating predicate) and range witnesses for gt/geq/eq_int
# (Phase 3) are NOT implemented here. substr/find_substr are
# deliberately given no witness at all -- their backward image is
# unconstrained (an arbitrary string/position doesn't decompose into a
# small candidate set) -- see the design doc for why that's a real
# architectural limit, not an oversight, and why it still doesn't make
# this pointless (arithmetic wrapping their results still narrows
# targets even though they can't be stepped through directly).
# Layer 2 of general bottom-up program synthesis for the GOAP goal solver
# (see plan: general bottom-up program synthesis). A bottom-up ENUMERATIVE
# synthesizer: given input/output examples, searches compositions of
# self_hosting/lib/primitive_registry.patlang's registered primitives for
# the smallest expression that reproduces every example exactly -- classic
# FlashFill/Blaze-style enumerative program synthesis, deliberately a
# different technique from self_hosting/lib/synthesis_*.patlang's
# predicate/rule induction (LGG/anti-unification feeding rule_add/solve):
# this searches over PRIMITIVE OPERATIONS composed into a VALUE, not over
# predicate names composed into a rule.
#
# Program representation: parser.patlang's own tagged-list AST node shape
# (["Const", v], ["Call", name, [args...]]), extended here with
# ["Input", param_name] for a formal parameter reference and ["If", cond,
# then, else] for the separate decision-list synthesis mode below -- so a
# winning candidate can, in principle, be pretty-printed the same way
# lib/parser.patlang's own ast_to_str already knows how.
#
# Example representation: a list of [bindings, expected_output] pairs,
# `bindings` a Dict of param-name -> value (matches self_hosting/lib/
# synthesis.patlang's [input, output] pair convention, just with named
# params since these functions can take more than one argument).
# Layer 1 of general bottom-up program synthesis for the GOAP goal solver
# (see plan: general bottom-up program synthesis). A registry of PRIMITIVE
# operations, each wrapped to a uniform try_<name>(args...) -> [ok, value]
# calling convention, with a per-primitive contract and a per-language code
# snippet dictionary -- so a later enumerative synthesizer (self_hosting/
# lib/synthesis_by_example.patlang) can search over primitives it never
# has to special-case as "pure" vs "effectful", and so a winning candidate
# can be emitted as source in more than just PatLang.
#
# Why every wrapper is hand-written rather than derived automatically: the
# real primitive surface (rust-runtime/src/ir/hosts.rs) is inconsistent --
# read-accessors (substr, char_code) silently clamp/sentinel on bad input
# and never fail; mutating ops (list_set) and file I/O raise a hard Err;
# only the tcp_* family has a genuine host-level try_ pairing already
# (tcp_connect/tcp_try_connect, see self_hosting/lib/signals.patlang's own
# header on why). PatLang has no try/catch, so a raised host Err can't be
# caught from inside PatLang code -- exactly why tcp_try_* exist as
# separate host entry points instead of a catchable wrapper, and exactly
# why each wrapper below checks its own precondition with a plain `if`
# BEFORE calling the real primitive, rather than trying to catch a failure
# after the fact.
#
# Contracts, correctly: require/ensure (-> contract_check, rust-runtime/
# src/ir/lowering.rs:365-374) are FATAL on violation -- confirmed via
# self_hosting/examples/contracts_demo.patlang. A synthesizer that tries
# many candidate calls, many of them intentionally invalid, cannot use
# require for the real failure path (that would abort the whole search on
# the first bad candidate). So every wrapper's real failure path is a
# plain `if`/early-return; require/ensure are used only to defend an
# invariant that should NEVER actually fire once the manual guard has
# already passed -- e.g. "the result this wrapper returns is always a
# 2-element [ok, value] list" -- giving every wrapper a real, checked
# contract without making the search fatal on an expected miss.
# Gherkin-driven contract clauses for GOAP synthesis (GitHub issue #12).
#
# Adds "And require <expr>" / "And ensure <expr>" as real, checked steps
# in a .feature scenario, WITHOUT encoding them as GOAP GroundFacts: a
# scalar comparison like `x < 10` isn't a unifiable ground predicate the
# way action_add's preconditions/effects are (see hosts.rs's
# parse_ground_facts/ground_action_instances) -- inventing an infinite
# family of numeric facts to represent every possible comparison isn't
# how the search space works, and isn't what require/ensure mean
# elsewhere in the language either (a runtime-evaluated boolean over live
# values, not a search-time predicate).
#
# Instead: a require/ensure clause is parsed into [var, op, literal],
# looked up against the SAME global __vars store set_var/get already use
# (get("__vars", var) -- the convention a Given step establishes: "Given
# an integer x" binds the global variable named exactly "x"), and
# evaluated as a plain boolean guard. Convention, not coincidence: this
# mirrors how ordinary require/ensure statements in hand-written PatLang
# functions are evaluated against real bound values, just triggered from
# a Gherkin step instead of a function body.
#
# Deliberately narrow grammar (see the design discussion in GitHub issue
# #12 and the plan that shipped this): <ident> <op> <literal>, exactly
# three space-separated tokens, <op> one of < <= > >= == !=, <literal> an
# integer. This does NOT reuse parser.patlang's full expression grammar --
# that would be a large, unwarranted dependency from the Gherkin runner
# onto the compiler's own parser internals for a single binary comparison.
# Self-hosted mirror of rust-runtime/src/preprocess.rs's expand_includes:
# expands `include "relative/path.patlang"` lines by splicing the
# referenced file's contents in place, resolving paths relative to the
# including file's own directory, recursively.
#
# Why this exists as PatLang, not just Rust: `expand_includes` was
# previously a NATIVE-ONLY preprocessing step (main.rs, run before the
# frontend ever sees the source) -- patc1.exe's own self-hosted lexer/
# parser never learned to do this, so any .patlang file using `include`
# could only be compiled via the native pat.exe frontend (`--ir-run`/
# `--patc`), never handed directly to patc1.exe, which is why every
# multi-file portfolio demo in build_portfolio.patlang manually
# concatenates dependency files (read_file(lexer) + chr(10) + ...) instead
# of using `include`. This closes that gap so `include` works identically
# everywhere -- interpreted, natively compiled, and self-hosted-compiled --
# matching this session's usual bar of "verified across all three paths."
#
# Kept as its own small library (not folded directly into patc1_main.patlang)
# so any self-hosted driver can `include "lib/includes.patlang"` and use it.
# str_trim(s) -> s with leading/trailing space/tab/\r/\n stripped.
# GitHub #22: \n was deliberately excluded here originally; audited every
# call site before changing this shared utility's semantics (per the
# issue's own explicit request not to "fix" it without checking callers
# first). Every current caller either trims an already-line-split string
# (no embedded \n to lose) or explicitly WANTS trailing newlines stripped
# (the two run_benchmarks.patlang/webcrawler.patlang callers comparing a
# captured-output blob across execution paths -- the original bug report
# that surfaced this: str_trim() alone didn't close a trailing-newline
# difference, needing a separate local helper to finish the job). No
# caller relies on \n being preserved through a trim call.
make a function called str_trim takes s returns trimmed
let n = s.length
let start = 0
while (start < n) and is_ws_char(char_code(s, start)) do
let start = start + 1
end
let end = n
while (end > start) and is_ws_char(char_code(s, end - 1)) do
let end = end - 1
end
return substr(s, start, end - start)
end
make a function called is_ws_char takes code returns is_ws
return (code == 32) or (code == 9) or (code == 13) or (code == 10)
end
# str_starts_with(s, prefix) -> bool
make a function called str_starts_with takes s, prefix returns matches
if prefix.length > s.length then
return false
end
return substr(s, 0, prefix.length) == prefix
end
# split_lines(s) -> list of lines, split on \n (a trailing \r on each line,
# from CRLF source files, is stripped too).
make a function called split_lines takes s returns lines
let out = []
let n = s.length
let start = 0
let i = 0
while i < n do
if char_code(s, i) == 10 then
let raw = substr(s, start, i - start)
let out = list_push(out, strip_trailing_cr(raw))
let start = i + 1
end
let i = i + 1
end
if start < n then
let out = list_push(out, strip_trailing_cr(substr(s, start, n - start)))
end
return out
end
make a function called strip_trailing_cr takes line returns stripped
let n = line.length
if (n > 0) and (char_code(line, n - 1) == 13) then
return substr(line, 0, n - 1)
end
return line
end
# path_dirname(path) -> everything before the last '/' or '\', or "." if
# the path has no directory component. Handles both separators since
# build_portfolio.patlang and friends run on Windows but write forward
# slashes in string literals.
make a function called path_dirname takes path returns dir
let n = path.length
let i = n - 1
let last_sep = -1
while i >= 0 do
let c = char_code(path, i)
if (c == 47) or (c == 92) then
let last_sep = i
let i = -1
else
let i = i - 1
end
end
if last_sep < 0 then
return "."
end
return substr(path, 0, last_sep)
end
# path_basename(path) -> everything after the last '/' or '\', or the
# whole path if it has no directory component -- the complement of
# path_dirname above (same separator-scanning loop, opposite half kept).
make a function called path_basename takes path returns base
let n = path.length
let i = n - 1
let last_sep = -1
while i >= 0 do
let c = char_code(path, i)
if (c == 47) or (c == 92) then
let last_sep = i
let i = -1
else
let i = i - 1
end
end
if last_sep < 0 then
return path
end
return substr(path, last_sep + 1, n - last_sep - 1)
end
# path_join(base, rel) -> base + "/" + rel, tolerating a trailing slash on
# base and an empty base (meaning "current directory"). If `rel` is itself
# absolute (leading '/'/'\', or a Windows drive letter like "C:"), it's
# returned unchanged, ignoring base -- matches Rust's PathBuf::join, which
# preprocess.rs's native expand_includes relies on for the same case.
make a function called path_join takes base, rel returns joined
if is_absolute_path(rel) then
return rel
end
if (base == "") or (base == ".") then
return rel
end
let n = base.length
if (n > 0) and ((char_code(base, n - 1) == 47) or (char_code(base, n - 1) == 92)) then
return base + rel
end
return base + "/" + rel
end
make a function called is_absolute_path takes p returns is_abs
if p.length == 0 then
return false
end
let c0 = char_code(p, 0)
if (c0 == 47) or (c0 == 92) then
return true
end
if (p.length >= 2) and (char_code(p, 1) == 58) then
return true
end
return false
end
# expand_includes(source, base_dir) -> source with every `include "path"`
# line recursively replaced by that file's own (recursively expanded)
# contents, paths resolved relative to base_dir (the including file's own
# directory) at each level, exactly matching preprocess.rs's semantics.
#
# The depth cap (16, matching preprocess.rs's MAX_DEPTH) is inlined as a
# literal below rather than a top-level `let` constant referenced from
# inside expand_includes_at_depth -- patc1.exe was found, while building
# this, to NOT make top-level `let` constants visible inside function
# bodies at all (confirmed via a minimal repro: the value silently reads
# as empty/unset, not an error) even though both --ir-run and native
# --patc handle this correctly. That's a real, previously-unknown
# self-hosted-compiler bug, logged separately in the backlog for its own
# dedicated fix -- this file just avoids relying on the broken behavior.
make a function called expand_includes takes source, base_dir returns expanded
return expand_includes_at_depth(source, base_dir, 0)
end
make a function called expand_includes_at_depth takes source, base_dir, depth returns expanded
if depth > 16 then
print("include: nesting deeper than 16 levels (cycle?)")
return source
end
let lines = split_lines(source)
let out = sb_new()
let i = 0
let n = to_num(list_len(lines))
while i < n do
let line = lines[i]
let t = str_trim(line)
if str_starts_with(t, "include ") and (str_starts_with(t, "#") == false) then
let rel = str_trim(substr(t, 8, t.length - 8))
let rel = strip_quotes(rel)
let path = path_join(base_dir, rel)
let inner = read_file(path)
let inner_base = path_dirname(path)
sb_push(out, expand_includes_at_depth(inner, inner_base, depth + 1))
sb_push(out, chr(10))
else
sb_push(out, line)
sb_push(out, chr(10))
end
let i = i + 1
end
return sb_str(out)
end
# strip_quotes("\"path\"") -> "path" -- include lines are always written
# with double-quoted paths, same as the native preprocessor expects.
make a function called strip_quotes takes s returns unquoted
let n = s.length
if (n >= 2) and (char_code(s, 0) == 34) and (char_code(s, n - 1) == 34) then
return substr(s, 1, n - 2)
end
return s
end
make a function called gc_split_ws takes s returns parts
let parts = []
let cur = sb_new()
let i = 0
while i < s.length do
let c = char_code(s, i)
if c == 32 then
if sb_str(cur).length > 0 then
let parts = list_push(parts, sb_str(cur))
let cur = sb_new()
end
else
sb_push(cur, s[i])
end
let i = i + 1
end
if sb_str(cur).length > 0 then
let parts = list_push(parts, sb_str(cur))
end
return parts
end
# parse_contract_clause("x < 10") -> ["x", "<", "10"]
# On malformed input (not exactly 3 tokens), returns ["ERR", message].
make a function called parse_contract_clause takes text returns clause
let tokens = gc_split_ws(text)
if to_num(list_len(tokens)) != 3 then
return ["ERR", "malformed contract clause (expected '<ident> <op> <literal>'): " + text]
end
return tokens
end
make a function called eval_cmp takes op, lhs, rhs returns ok
if op == "<" then
return lhs < rhs
end
if op == "<=" then
return lhs <= rhs
end
if op == ">" then
return lhs > rhs
end
if op == ">=" then
return lhs >= rhs
end
if op == "==" then
return lhs == rhs
end
if op == "!=" then
return lhs != rhs
end
return false
end
# GitHub #49: representation/type invariants (e.g. `ensure x_kind == "bigint"`)
# compare a bound value against a NON-numeric literal, so the ident/op/literal
# grammar can't blindly to_num() both sides the way the original numeric-only
# design did. Ordering-only (< <= > >=) still requires numbers -- there's no
# sensible non-numeric ordering here -- but == and != fall back to raw string
# comparison whenever either side fails to parse as a number.
make a function called looks_numeric takes s returns ok
return to_num(s) or (s == "0")
end
make a function called eval_cmp_typed takes op, lhs_raw, rhs_raw returns ok
if (op == "==") or (op == "!=") then
if looks_numeric(lhs_raw) and looks_numeric(rhs_raw) then
return eval_cmp(op, to_num(lhs_raw), to_num(rhs_raw))
else
return eval_cmp(op, lhs_raw, rhs_raw)
end
end
return eval_cmp(op, to_num(lhs_raw), to_num(rhs_raw))
end
# handle_contract_step(kind, clause_text): kind is "require" or "ensure",
# clause_text is the raw text after that keyword (e.g. "x < 10").
#
# Two modes, chosen automatically by whether the clause's variable is
# already bound:
# - IMMEDIATE: a prior Given step already set_var'd this exact variable
# name (the hand-written-function case, Slice 1) -- evaluated right
# away against that bound value, exactly like an ordinary require/
# ensure statement would be. A violation here records a real t_fail,
# same convention as an undefined step.
# - DEFERRED: the variable isn't bound yet (a GOAP synthesis hasn't run
# yet -- Slice 2's case, where the value only becomes known from the
# winning plan's own bindings). The parsed clause is stashed onto
# "t_pending_contracts" for a later goap_verify_contracts call to
# consume, once real bindings exist. Deliberately does NOT touch
# t_fail here -- whether a deferred clause holding or not is itself
# the very thing a scenario may be testing (see goap_verify_contracts),
# so recording pass/fail is left to the scenario's own explicit check.
make a function called handle_contract_step takes kind, clause_text returns done
let clause = parse_contract_clause(clause_text)
if list_get(clause, 0) == "ERR" then
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: " + list_get(clause, 1))
return true
end
let var_name = list_get(clause, 0)
let op = list_get(clause, 1)
let literal = list_get(clause, 2)
let already_bound = get("__vars", var_name)
if already_bound then
let ok = eval_cmp_typed(op, already_bound, literal)
if ok then
print(" ok: " + kind + " " + clause_text)
else
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: " + kind + " violated: " + clause_text)
end
else
let pending = get("__vars", "t_pending_contracts")
if pending then
let pending = list_push(pending, [kind, var_name, op, literal])
else
let pending = [[kind, var_name, op, literal]]
end
set_var("t_pending_contracts", pending)
print(" (deferred) " + kind + " " + clause_text)
end
return true
end
make a function called gc_find_substr takes hay, needle returns idx
if needle.length == 0 then
return 0
end
let i = 0
while i <= (hay.length - needle.length) do
if substr(hay, i, needle.length) == needle then
return i
end
let i = i + 1
end
return -1
end
# Extract the bound value of `var_name` from a GOAP plan-step label like
# "scale(X=5)" or "assemble(X=final,Y=base)" (see action_instance_label,
# rust-runtime/src/ir/hosts.rs). Returns "" if that label doesn't bind
# this variable at all.
make a function called gc_extract_binding takes label, var_name returns value
let needle = var_name + "="
let idx = gc_find_substr(label, needle)
if idx < 0 then
return ""
end
let start = idx + needle.length
let i = start
let scanning = true
while (i < label.length) and scanning do
let c = label[i]
if (c == ",") or (c == ")") then
let scanning = false
else
let i = i + 1
end
end
return substr(label, start, i - start)
end
# goap_verify_contracts(clauses, plan_labels) -> ok
#
# clauses: a list of ["require"|"ensure", var, op, literal] tuples, e.g.
# what handle_contract_step stashes onto "t_pending_contracts" while
# deferred. plan_labels: the list of strings plan() returns.
#
# Evaluates each clause against whichever plan step's label actually
# binds that variable -- the guard is checked once against the concrete
# value GOAP's search settled on, BEFORE that candidate is accepted or
# any code is generated for it (see the design note at the top of this
# file). A clause referencing a variable no step binds at all is treated
# as a failure (there is nothing real to check it against). Prints an
# ok/FAIL diagnostic per clause but deliberately does NOT touch t_fail
# itself -- the caller decides, via its own check(...), whether the
# returned boolean was the outcome that scenario expected (a deliberately
# violating candidate being correctly rejected is itself a PASSING test).
make a function called goap_verify_contracts takes clauses, plan_labels returns ok
let all_ok = true
let ci = 0
let cn = to_num(list_len(clauses))
while ci < cn do
let clause = list_get(clauses, ci)
let kind = list_get(clause, 0)
let var_name = list_get(clause, 1)
let op = list_get(clause, 2)
let literal = to_num(list_get(clause, 3))
let found = false
let li = 0
let ln = to_num(list_len(plan_labels))
while (li < ln) and (found == false) do
let label = list_get(plan_labels, li)
let raw = gc_extract_binding(label, var_name)
if raw != "" then
let found = true
let bound = to_num(raw)
let ok = eval_cmp(op, bound, literal)
if ok then
print(" ok: " + kind + " " + var_name + " " + op + " " + list_get(clause, 3) + " (from " + label + ")")
else
print(" FAIL: " + kind + " violated by synthesized plan: " + label)
let all_ok = false
end
end
let li = li + 1
end
if found == false then
print(" FAIL: " + kind + " references a variable no plan step binds: " + var_name)
let all_ok = false
end
let ci = ci + 1
end
return all_ok
end
# new("Dict", name) is a GLOBAL object keyed by that literal name string
# (rust-runtime/src/ir/hosts.rs's OBJECTS map) -- two calls with the same
# name alias the SAME object rather than creating independent ones. Every
# Dict this file creates therefore gets a fresh, process-unique name via
# this counter, never a fixed literal.
make a function called pr_next_id returns id
let cur = get("__vars", "pr_id_counter")
let n = 0
if cur then
let n = to_num(cur)
end
set_var("pr_id_counter", n + 1)
return n
end
make a function called pr_new_registry returns registry
return new("Dict", "primitive_registry_" + pr_next_id())
end
# entry: ["prim", try_fn_name, arity, cost, snippets, arg_types, ret_type,
# arg_contracts] for a hand-written primitive wrapper, or ["composite",
# [ast, param_names], arity, cost, snippets, arg_types, ret_type,
# arg_contracts] for a function synthesis_by_example.patlang derived from
# examples and registered back in (see register_composite there) -- the
# "kind" tag at index 0 is what lets both live in the same registry and
# be dispatched uniformly by the enumerator's evaluator. snippets is a
# Dict from language name -> template string with positional {0}/{1}/...
# placeholders.
#
# arg_types is a list of "int"/"string"/"bool"/"list" tags, one per
# argument position -- comparisons on mismatched types are a FATAL
# interpreter error in PatLang (confirmed empirically: `code < 0` on a
# string argument aborts the whole process, not just that call), so the
# enumerator MUST filter candidate arguments by inferred type before ever
# constructing a call, never discover a type mismatch by trying it and
# catching a failure.
#
# ret_type is the type this primitive PRODUCES (declared, not inferred --
# a composite's actual output type still comes from evaluating it, but a
# raw primitive's doesn't change per call the way a composite's might
# depend on its own internals, so it's simplest to just state it).
# "any" is reserved for a genuinely polymorphic primitive (list_get's
# return type is whatever the list holds) -- pr_names_for_ret_type treats
# "any"-tagged primitives as a candidate for every requested type.
#
# arg_contracts is a list, one per argument position, of either "" (no
# extra contract beyond the type tag) or a predicate FUNCTION NAME that
# takes the argument's actual value (on the sample binding) and returns a
# bool -- checked BEFORE a candidate is even constructed, not after,
# pruning combinations that are provably inadmissible (e.g. a negative
# substr count) rather than building-then-rejecting them via full
# evaluation. This is deliberately unary/per-position only -- a RELATIONAL
# contract across two argument positions (e.g. "start <= text.length") is
# still enforced the way it always was, inside the try_ wrapper itself at
# evaluation time, not pruned at construction time; expressing that
# relationally at construction time is a real further improvement, not
# attempted here (see the plan's explicit non-goal on unifying this with
# the GOAP planner's own effect/precondition language).
make a function called pr_register takes registry, name, try_fn_name, arity, cost, snippets, arg_types, ret_type, arg_contracts returns done
send(registry, "set", name, ["prim", try_fn_name, arity, cost, snippets, arg_types, ret_type, arg_contracts])
let idx = get(registry, "__by_ret_type__")
if not idx then
let idx = new("Dict", "pr_by_ret_type_" + pr_next_id())
send(registry, "set", "__by_ret_type__", idx)
end
let existing = get(idx, ret_type)
if existing then
send(idx, "set", ret_type, list_push(existing, name))
else
send(idx, "set", ret_type, [name])
end
return true
end
make a function called pr_lookup takes registry, name returns entry
return get(registry, name)
end
# Every primitive/composite registered with the given ret_type, PLUS
# every one registered as "any" (a genuinely polymorphic producer) --
# lets a caller ask "what can produce a string?" instead of hand-curating
# a primitive_names list per demo, the "more realistic action set" this
# was built for.
make a function called pr_names_for_ret_type takes registry, ret_type returns names
let idx = get(registry, "__by_ret_type__")
if not idx then
return []
end
let exact = get(idx, ret_type)
if not exact then
let exact = []
end
if ret_type == "any" then
return exact
end
let poly = get(idx, "any")
if not poly then
return exact
end
return sbe_map_json_str_free(exact, poly)
end
# Plain list concatenation, named locally so this file doesn't need to
# include synthesis_by_example.patlang (which includes THIS file) just
# for sbe_list_concat.
make a function called sbe_map_json_str_free takes a, b returns out
let out = a
let i = 0
let n = to_num(list_len(b))
while i < n do
let out = list_push(out, b[i])
let i = i + 1
end
return out
end
# Checks arg_contracts (if any) for the given primitive against the
# ACTUAL VALUES a candidate call's arguments would take on the sample
# binding -- true if every declared per-position contract passes (or has
# none declared).
make a function called pr_args_satisfy_contracts takes entry, arg_values returns ok
let arg_contracts = entry[7]
let i = 0
let n = to_num(list_len(arg_contracts))
while i < n do
let contract_fn = arg_contracts[i]
if contract_fn != "" then
if not apply(contract_fn, arg_values[i]) then
return false
end
end
let i = i + 1
end
return true
end
# ---- reusable arg-contract predicates ----
make a function called pr_contract_nonneg takes v returns ok
return v >= 0
end
make a function called pr_snippet takes registry, name, lang returns tmpl
let entry = pr_lookup(registry, name)
if entry then
let snippets = entry[4]
let t = get(snippets, lang)
if t then
return t
end
end
return ""
end
make a function called pr_new_snippets returns d
return new("Dict", "primitive_snippets_" + pr_next_id())
end
make a function called pr_set_snippet takes snippets, lang, tmpl returns done
send(snippets, "set", lang, tmpl)
return true
end
# ---- try_ wrappers: the uniform [ok, value] calling convention ----
make a function called try_chr takes code returns result
if (code < 0) or (code > 1114111) then
let result = [false, ""]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, chr(code)]
ensure to_num(list_len(result)) == 2
return result
end
# char_code(s, idx) sentinel-returns -1 on an out-of-range index (verified
# in rust-runtime/src/ir/hosts.rs) rather than raising -- treated here as
# the wrapper's real, meaningful failure signal.
make a function called try_char_code takes s, idx returns result
let c = char_code(s, idx)
if c < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, c]
ensure to_num(list_len(result)) == 2
return result
end
# substr(s, start, count) clamps/saturates rather than raising (verified
# in hosts.rs) -- the manual guard below is what makes an out-of-range
# start a real, observable failure instead of a silently truncated result.
make a function called try_substr takes s, start, count returns result
if (start < 0) or (start > s.length) or (count < 0) then
let result = [false, ""]
ensure to_num(list_len(result)) == 2
return result
end
require (start >= 0) and (start <= s.length)
let result = [true, substr(s, start, count)]
ensure to_num(list_len(result)) == 2
return result
end
# String concatenation, equality, and length never fail -- always ok, kept
# in the uniform [ok, value] shape purely for the enumerator's calling
# convention.
make a function called try_concat takes a, b returns result
let result = [true, a + b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_str_eq takes a, b returns result
let result = [true, a == b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_str_len takes s returns result
let result = [true, s.length]
ensure to_num(list_len(result)) == 2
return result
end
# Wraps the existing library scan (self_hosting/lib/gherkin_contracts.
# patlang's gc_find_substr) rather than reimplementing it -- the registry
# doesn't care whether a primitive is host- or library-implemented, only
# that it has a wrapper of the uniform shape.
#
# Two variants, deliberately: try_find_substr treats "not found" as a real
# FAILURE (ok=false) -- useful when a composition should be rejected
# outright if the needle is absent. try_index_of treats "not found" as a
# perfectly valid VALUE (-1) that a later comparison can act on (e.g.
# `index_of(...) >= 0` as a presence test) -- needed because sbe_eval
# short-circuits a whole candidate to non-matching the moment any sub-call
# comes back not-ok, which would make a presence test like es_contains
# unreachable if find_substr's fail-on-absence were the only option.
make a function called try_find_substr takes hay, needle returns result
let idx = gc_find_substr(hay, needle)
if idx < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, idx]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_index_of takes hay, needle returns result
let result = [true, gc_find_substr(hay, needle)]
ensure to_num(list_len(result)) == 2
return result
end
# Search starting from a given offset (needed to find a SECOND
# occurrence of a delimiter, e.g. Markdown's closing "**" -- ordinary
# find_substr/index_of always find the FIRST occurrence from the start).
make a function called try_index_of_from takes hay, needle, start returns result
if (start < 0) or (start > hay.length) then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let rest = substr(hay, start, hay.length - start)
let found = gc_find_substr(rest, needle)
if found < 0 then
let result = [true, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, found + start]
ensure to_num(list_len(result)) == 2
return result
end
# Small arithmetic/comparison primitives -- never fail, needed so the
# enumerator can compose index arithmetic (e.g. "one past the delimiter")
# the same way it composes string operations.
make a function called try_add takes a, b returns result
let result = [true, a + b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_sub takes a, b returns result
let result = [true, a - b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_geq takes a, b returns result
let result = [true, a >= b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_gt takes a, b returns result
let result = [true, a > b]
ensure to_num(list_len(result)) == 2
return result
end
# cond(test, a, b) -> a if test else b. Never fails; deliberately doesn't
# type-check a/b against each other -- it just returns whichever branch
# the caller asked for. This is what lets the enumerator express genuine
# conditional SELECTION (as opposed to the separate decision-list mode's
# literal-equality branching) as an ordinary Call node, without adding a
# new AST node kind: "which of two already-computed values is the right
# one" becomes composable the same way any other primitive is.
# PatLang has no inline ternary expression, only an `if` statement -- this
# is the plain-function equivalent used by "cond"'s own emitted call-site
# snippet (sbe_pat_cond({0}, {1}, {2})), so generated source that includes
# this file can actually call the emitted expression.
make a function called sbe_pat_cond takes test, a, b returns result
if test then
return a
end
return b
end
make a function called try_cond takes test, a, b returns result
if test then
let result = [true, a]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_eq_int takes a, b returns result
let result = [true, a == b]
ensure to_num(list_len(result)) == 2
return result
end
# list_get(xs, idx) returns Unit/empty on an out-of-range index rather
# than raising (verified in rust-runtime/src/ir/hosts.rs) -- the manual
# guard below is what makes an out-of-range index a real, observable
# failure instead of an ambiguous "empty" result.
make a function called try_list_get takes xs, idx returns result
if (idx < 0) or (idx >= to_num(list_len(xs))) then
let result = [false, ""]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, list_get(xs, idx)]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_list_len takes xs returns result
let result = [true, to_num(list_len(xs))]
ensure to_num(list_len(result)) == 2
return result
end
# ---- effectful primitives: same uniform shape, same contract discipline.
# tcp_try_connect/tcp_try_listen already exist at the host level (the
# "real try_ pairing" case) -- these wrappers just normalize their
# -1-on-failure sentinel into the same [ok, value] convention every other
# registrant uses, so the enumerator never has to special-case them.
make a function called try_tcp_connect takes host, port returns result
let id = tcp_try_connect(host, port)
if id < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, id]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_tcp_listen takes port returns result
let id = tcp_try_listen(port)
if id < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, id]
ensure to_num(list_len(result)) == 2
return result
end
# ---- the standard registry: every primitive above, registered with its
# arity, a search cost, and a per-language snippet dictionary. "patlang"
# is always present (its template is just the real primitive call text);
# other languages are added incrementally, one snippet at a time, per
# primitive -- adding a new target language never requires a new
# per-node-kind transpiler (contrast self_hosting/lib/transpile_ruby.
# patlang's whole-AST walker), just one template per primitive you want
# callable from it.
make a function called pr_standard_registry returns registry
let registry = pr_new_registry()
let s_chr = pr_new_snippets()
pr_set_snippet(s_chr, "patlang", "chr({0})")
pr_set_snippet(s_chr, "ruby", "({0}).chr")
pr_set_snippet(s_chr, "python", "chr({0})")
pr_register(registry, "chr", "try_chr", 1, 1, s_chr, ["int"], "string", [""])
let s_char_code = pr_new_snippets()
pr_set_snippet(s_char_code, "patlang", "char_code({0}, {1})")
pr_set_snippet(s_char_code, "ruby", "({0}).getbyte({1})")
pr_set_snippet(s_char_code, "python", "ord({0}[{1}])")
pr_register(registry, "char_code", "try_char_code", 2, 1, s_char_code, ["string", "int"], "int", ["", "pr_contract_nonneg"])
let s_substr = pr_new_snippets()
pr_set_snippet(s_substr, "patlang", "substr({0}, {1}, {2})")
pr_set_snippet(s_substr, "ruby", "({0})[{1}, {2}]")
pr_set_snippet(s_substr, "python", "({0})[{1}:{1}+{2}]")
pr_register(registry, "substr", "try_substr", 3, 1, s_substr, ["string", "int", "int"], "string", ["", "pr_contract_nonneg", "pr_contract_nonneg"])
let s_concat = pr_new_snippets()
pr_set_snippet(s_concat, "patlang", "({0} + {1})")
pr_set_snippet(s_concat, "ruby", "({0} + {1})")
pr_set_snippet(s_concat, "python", "({0} + {1})")
pr_register(registry, "concat", "try_concat", 2, 1, s_concat, ["string", "string"], "string", ["", ""])
let s_str_eq = pr_new_snippets()
pr_set_snippet(s_str_eq, "patlang", "({0} == {1})")
pr_set_snippet(s_str_eq, "ruby", "({0} == {1})")
pr_set_snippet(s_str_eq, "python", "({0} == {1})")
pr_register(registry, "str_eq", "try_str_eq", 2, 1, s_str_eq, ["string", "string"], "bool", ["", ""])
let s_str_len = pr_new_snippets()
pr_set_snippet(s_str_len, "patlang", "({0}).length")
pr_set_snippet(s_str_len, "ruby", "({0}).length")
pr_set_snippet(s_str_len, "python", "len({0})")
pr_register(registry, "str_len", "try_str_len", 1, 1, s_str_len, ["string"], "int", [""])
let s_find_substr = pr_new_snippets()
pr_set_snippet(s_find_substr, "patlang", "gc_find_substr({0}, {1})")
pr_set_snippet(s_find_substr, "ruby", "(({0}).index({1}) or -1)")
pr_set_snippet(s_find_substr, "python", "({0}).find({1})")
pr_register(registry, "find_substr", "try_find_substr", 2, 1, s_find_substr, ["string", "string"], "int", ["", ""])
let s_index_of = pr_new_snippets()
pr_set_snippet(s_index_of, "patlang", "gc_find_substr({0}, {1})")
pr_set_snippet(s_index_of, "ruby", "(({0}).index({1}) or -1)")
pr_set_snippet(s_index_of, "python", "({0}).find({1})")
pr_register(registry, "index_of", "try_index_of", 2, 1, s_index_of, ["string", "string"], "int", ["", ""])
# NOTE: this call-site template is only correct when the needle IS
# found (it doesn't special-case gc_find_substr's -1-not-found sentinel
# the way try_index_of_from itself does) -- fine for emitting source
# that's only ever run on inputs already known (via the examples that
# proved it) to contain a match; not used by sbe_eval's own direct
# evaluation path, which always calls the real try_ function.
let s_index_of_from = pr_new_snippets()
pr_set_snippet(s_index_of_from, "patlang", "(gc_find_substr(substr({0}, {2}, ({0}).length - {2}), {1}) + {2})")
pr_register(registry, "index_of_from", "try_index_of_from", 3, 2, s_index_of_from, ["string", "string", "int"], "int", ["", "", "pr_contract_nonneg"])
let s_add = pr_new_snippets()
pr_set_snippet(s_add, "patlang", "({0} + {1})")
pr_set_snippet(s_add, "ruby", "({0} + {1})")
pr_set_snippet(s_add, "python", "({0} + {1})")
pr_register(registry, "add", "try_add", 2, 1, s_add, ["int", "int"], "int", ["", ""])
let s_sub = pr_new_snippets()
pr_set_snippet(s_sub, "patlang", "({0} - {1})")
pr_set_snippet(s_sub, "ruby", "({0} - {1})")
pr_set_snippet(s_sub, "python", "({0} - {1})")
pr_register(registry, "sub", "try_sub", 2, 1, s_sub, ["int", "int"], "int", ["", ""])
let s_geq = pr_new_snippets()
pr_set_snippet(s_geq, "patlang", "({0} >= {1})")
pr_set_snippet(s_geq, "ruby", "({0} >= {1})")
pr_set_snippet(s_geq, "python", "({0} >= {1})")
pr_register(registry, "geq", "try_geq", 2, 1, s_geq, ["int", "int"], "bool", ["", ""])
let s_gt = pr_new_snippets()
pr_set_snippet(s_gt, "patlang", "({0} > {1})")
pr_set_snippet(s_gt, "ruby", "({0} > {1})")
pr_set_snippet(s_gt, "python", "({0} > {1})")
pr_register(registry, "gt", "try_gt", 2, 1, s_gt, ["int", "int"], "bool", ["", ""])
let s_cond = pr_new_snippets()
pr_set_snippet(s_cond, "patlang", "sbe_pat_cond({0}, {1}, {2})")
pr_register(registry, "cond", "try_cond", 3, 1, s_cond, ["bool", "any", "any"], "any", ["", "", ""])
let s_eq_int = pr_new_snippets()
pr_set_snippet(s_eq_int, "patlang", "({0} == {1})")
pr_set_snippet(s_eq_int, "ruby", "({0} == {1})")
pr_set_snippet(s_eq_int, "python", "({0} == {1})")
pr_register(registry, "eq_int", "try_eq_int", 2, 1, s_eq_int, ["int", "int"], "bool", ["", ""])
let s_list_get = pr_new_snippets()
pr_set_snippet(s_list_get, "patlang", "list_get({0}, {1})")
pr_set_snippet(s_list_get, "ruby", "({0})[{1}]")
pr_set_snippet(s_list_get, "python", "({0})[{1}]")
pr_register(registry, "list_get", "try_list_get", 2, 1, s_list_get, ["list", "int"], "any", ["", "pr_contract_nonneg"])
let s_list_len = pr_new_snippets()
pr_set_snippet(s_list_len, "patlang", "to_num(list_len({0}))")
pr_set_snippet(s_list_len, "ruby", "({0}).length")
pr_set_snippet(s_list_len, "python", "len({0})")
pr_register(registry, "list_len", "try_list_len", 1, 1, s_list_len, ["list"], "int", [""])
let s_tcp_connect = pr_new_snippets()
pr_set_snippet(s_tcp_connect, "patlang", "tcp_try_connect({0}, {1})")
pr_register(registry, "tcp_connect", "try_tcp_connect", 2, 5, s_tcp_connect, ["string", "int"], "int", ["", "pr_contract_nonneg"])
let s_tcp_listen = pr_new_snippets()
pr_set_snippet(s_tcp_listen, "patlang", "tcp_try_listen({0})")
pr_register(registry, "tcp_listen", "try_tcp_listen", 1, 5, s_tcp_listen, ["int"], "int", ["pr_contract_nonneg"])
return registry
end
# ---- evaluator ----
#
# Dispatches a Call node to its registry entry's real implementation --
# either a Layer-1 try_ wrapper (kind "prim") or a previously-derived
# composite's own stored AST (kind "composite", see register_composite
# below), replaying that composite's parameter bindings the same way a
# real function call would. If any sub-call comes back not-ok, the WHOLE
# candidate is rejected for that example (returned as [false, ...]) rather
# than aborting the search -- this is exactly why every Layer-1 wrapper is
# non-fatal (plain `if`, never a fatal require) on its real failure path.
make a function called sbe_call_prim takes try_fn, vals returns result
let n = to_num(list_len(vals))
if n == 0 then
return apply(try_fn)
end
if n == 1 then
return apply(try_fn, vals[0])
end
if n == 2 then
return apply(try_fn, vals[0], vals[1])
end
if n == 3 then
return apply(try_fn, vals[0], vals[1], vals[2])
end
if n == 4 then
return apply(try_fn, vals[0], vals[1], vals[2], vals[3])
end
return [false, "sbe_call_prim: unsupported arity " + n]
end
make a function called sbe_eval takes node, bindings, registry returns result
let tag = node[0]
if tag == "Const" then
return [true, node[1]]
end
if tag == "Input" then
return [true, get(bindings, node[1])]
end
if tag == "If" then
let cond = sbe_eval(node[1], bindings, registry)
if cond[0] == false then
return [false, ""]
end
if cond[1] then
return sbe_eval(node[2], bindings, registry)
end
return sbe_eval(node[3], bindings, registry)
end
if tag == "Call" then
let prim = node[1]
let arg_nodes = node[2]
let entry = pr_lookup(registry, prim)
if not entry then
return [false, ""]
end
let n = to_num(list_len(arg_nodes))
let vals = []
let all_ok = true
let i = 0
while i < n do
let sub = sbe_eval(arg_nodes[i], bindings, registry)
if sub[0] == false then
let all_ok = false
end
let vals = list_push(vals, sub[1])
let i = i + 1
end
if all_ok == false then
return [false, ""]
end
let kind = entry[0]
let impl = entry[1]
if kind == "prim" then
return sbe_call_prim(impl, vals)
end
# kind == "composite": impl = [inner_ast, param_names] -- replay the
# derived function's own body against ITS OWN parameter names, the
# same way any ordinary function call binds formal parameters.
let inner_ast = impl[0]
let param_names = impl[1]
let inner_bindings = new("Dict", "sbe_bind_" + pr_next_id())
let j = 0
while j < n do
send(inner_bindings, "set", param_names[j], vals[j])
let j = j + 1
end
return sbe_eval(inner_ast, inner_bindings, registry)
end
return [false, "sbe_eval: unknown node tag"]
end
# ---- size, filtering, candidate construction ----
make a function called sbe_size takes node returns n
let tag = node[0]
if tag == "Call" then
let args = node[2]
let total = 1
let i = 0
let m = to_num(list_len(args))
while i < m do
let total = total + sbe_size(args[i])
let i = i + 1
end
return total
end
if tag == "If" then
return 1 + sbe_size(node[1]) + sbe_size(node[2]) + sbe_size(node[3])
end
return 1
end
# Every candidate AST is tracked as a TYPED node [ast, size, type, value]
# once built -- `type` is type_of(...) of that AST's value when evaluated
# against a representative example's bindings ("int"/"string"/"bool", or
# "invalid" if that evaluation itself came back not-ok); `value` is that
# same computed value, kept alongside so a primitive's arg_contracts can
# be checked against it later without re-evaluating. This typing is
# required, not just an optimization: PatLang raises a FATAL interpreter
# error on a type-mismatched comparison (`code < 0` on a string aborts
# the whole process, confirmed empirically -- there is no try/catch to
# recover from it), so the search must know an argument's type BEFORE
# ever constructing a call with it, never discover a mismatch by
# attempting one.
make a function called sbe_infer_type_and_value takes node, registry, sample_bindings returns pair
let r = sbe_eval(node, sample_bindings, registry)
if r[0] == false then
return ["invalid", ""]
end
return [type_of(r[1]), r[1]]
end
make a function called sbe_wrap takes node, registry, sample_bindings returns typed
let tv = sbe_infer_type_and_value(node, registry, sample_bindings)
return [node, sbe_size(node), tv[0], tv[1]]
end
# ---- the candidate pool INDEX: a real (type -> size -> bucket) tree,
# not a flat list scanned on every lookup. sbe_build_calls used to call a
# linear-scan filter once per (primitive, argument position, size
# partition) -- with the pool itself growing multiplicatively every
# level, that repeated O(pool) scan compounded the blowup on top of the
# search space's own genuine growth (measured directly: a flat,
# non-decomposed search on replace_in_text grew from a 12s level to a
# 165s level across 3 levels, growing FASTER than the pool itself). This
# index turns "every size-5 string-typed node" into a couple of Dict
# lookups instead of a scan of everything ever built.
make a function called sbe_index_new returns index
return new("Dict", "sbe_index_" + pr_next_id())
end
make a function called sbe_index_add takes index, typed returns done
let ty = typed[2]
let size = typed[1]
let by_size = get(index, ty)
if not by_size then
let by_size = new("Dict", "sbe_index_bysize_" + pr_next_id())
send(index, "set", ty, by_size)
end
let size_key = "" + size
let bucket = get(by_size, size_key)
if not bucket then
let bucket = []
end
send(by_size, "set", size_key, list_push(bucket, typed))
return true
end
# Stores an entire (type, size) bucket in ONE Dict write. Only ever
# called with a size that has never been written for this type before
# (each level only ever produces nodes of exactly the current size, and
# sizes strictly increase), so this never has to merge with an existing
# bucket -- the caller (synthesize_from_examples) accumulates a level's
# new nodes in a plain LOCAL list first (cheap: a uniquely-held list, not
# aliased into any Dict, so list_push there is a genuine in-place O(1)
# amortized append -- see rust-runtime/src/ir/hosts.rs's own comment on
# host_list_push's Arc::make_mut: pushing onto a list some OTHER live
# reference still shares forces a full deep clone). Calling sbe_index_add
# once PER CANDIDATE during a level, instead of batching like this, was
# measured to make the search SLOWER than the original flat scan it was
# meant to replace -- every such call re-reads the bucket already stored
# in the Dict (aliasing its Arc), so the very next list_push onto it has
# to deep-clone the whole bucket first, turning insertion into O(bucket
# size) per candidate instead of O(1).
make a function called sbe_index_set_bucket takes index, ty, size, items returns done
let by_size = get(index, ty)
if not by_size then
let by_size = new("Dict", "sbe_index_bysize_" + pr_next_id())
send(index, "set", ty, by_size)
end
send(by_size, "set", "" + size, items)
return true
end
make a function called sbe_index_lookup takes index, size, ty returns bucket
let by_size = get(index, ty)
if not by_size then
return []
end
let bucket = get(by_size, "" + size)
if not bucket then
return []
end
return bucket
end
# ---- sliding-window memory bound (Design B) ----
#
# The index otherwise retains every surviving candidate from every level
# ever explored, unboundedly -- confirmed directly as the real memory
# driver behind GitHub issue #73 (the first_exceeding two-list case
# climbed past 20GB+ and kept growing well before finding a match).
# Parallelizing evaluation (Design A) only ever addressed wall-clock
# time, not this. Only the most recent `sbe_window_size()` composed
# levels are kept; older ones are evicted by overwriting their bucket
# with an empty list (no delete primitive needed -- sbe_index_lookup
# already treats empty and missing the same way, and dropping the last
# reference to the old list lets it actually be freed).
#
# Leaves (size 1 -- Input/Const) are NEVER evicted: they're cheap (a
# small, fixed set per search) and are exactly what a late-level
# candidate most often reaches back for -- confirmed directly in the
# actual first_exceeding formula this was built to fix, which reused
# list_get(xs, 1) (built from two size-1 leaves) deep inside a
# size-17+ AST. Windowing sizes >= 2 only, while keeping every leaf,
# is a real completeness/memory tradeoff, not a free lunch: a solution
# that needs a specific size-3+ intermediate piece combined only many
# levels later than the window allows could still be missed. State that
# plainly wherever this is described, not just here.
#
# 16, not 8: confirmed by real evidence, not picked in the abstract. The
# real first_exceeding two-list case (the one that originally hit
# GitHub issue #73's 45GB+ figure) genuinely needed a window this size --
# window=8 completed safely (no crash, no resource risk) but returned
# ERR, evicting a piece (list_get(xs,0)/list_get(xs,1), each reused deep
# in the winning AST) the TRUE general formula needed; window=16
# (effectively unbounded for this problem's own depth) found the exact
# same case's genuinely correct, non-overfit answer in ~53 minutes with
# memory staying healthy throughout (peaked well under what the
# unbounded/unchunked version needed, and ended with 45GB still free).
# A too-small window doesn't fail loudly -- it fails by returning a
# confident ERR for a solvable problem, which is worth remembering
# before treating a smaller window as a safe default for a new domain.
make a function called sbe_window_size returns w
let override = get("__vars", "sbe_window_size_override")
if override then
return to_num(override)
end
return 16
end
make a function called sbe_evict_size takes index, size returns done
if size < 2 then
return true
end
let types = sbe_concrete_types()
let t = 0
let tn = to_num(list_len(types))
while t < tn do
let by_size = get(index, types[t])
if by_size then
send(by_size, "set", "" + size, [])
end
let t = t + 1
end
return true
end
# The (size, type)-indexed bucket, ALSO filtered by a single-argument
# contract (self_hosting/lib/primitive_registry.patlang's arg_contracts)
# checked against each candidate's already-computed value -- so a
# provably-inadmissible argument (e.g. a negative substr count) is
# dropped before it's ever combined into a Call node, not generated then
# rejected by full evaluation. Returns raw AST nodes (the Call node needs
# the ast, not the bookkeeping).
# The 4 concrete runtime types sbe_infer_type_and_value can ever produce
# (never "any" -- that's a registry-declared wildcard, not a real
# runtime type, see primitive_registry.patlang's own note on this).
make a function called sbe_concrete_types returns tys
return ["int", "string", "bool", "list"]
end
# "any" argument position (e.g. cond's 2nd/3rd args): union every
# concrete type's bucket at this size, contract-filtered the same way a
# single concrete type would be -- lets a primitive genuinely accept a
# value of whatever type, needed for real conditional SELECTION (return
# whichever of two already-computed values a test picks) without the
# type system rejecting it outright.
make a function called sbe_index_lookup_filtered_any takes index, size, contract_fn returns out
let out = []
let types = sbe_concrete_types()
let t = 0
let tn = to_num(list_len(types))
while t < tn do
let out = sbe_list_concat(out, sbe_index_lookup_filtered(index, size, types[t], contract_fn))
let t = t + 1
end
return out
end
make a function called sbe_index_lookup_filtered takes index, size, ty, contract_fn returns out
if ty == "any" then
return sbe_index_lookup_filtered_any(index, size, contract_fn)
end
let bucket = sbe_index_lookup(index, size, ty)
if contract_fn == "" then
let out = []
let i = 0
let n = to_num(list_len(bucket))
while i < n do
let out = list_push(out, bucket[i][0])
let i = i + 1
end
return out
end
let out = []
let i = 0
let n = to_num(list_len(bucket))
while i < n do
let typed = bucket[i]
if apply(contract_fn, typed[3]) then
let out = list_push(out, typed[0])
end
let i = i + 1
end
return out
end
# All Call nodes of exactly target_size for a primitive with the given
# per-position arg_types/arg_contracts, drawing arguments from the INDEX
# (any smaller, type-tagged node already built), by partitioning
# target_size - 1 (the budget left after paying 1 for the Call itself)
# across the primitive's argument positions -- each position looked up
# directly by (size, type) and pruned by its own arg_contract, rather
# than scanned out of a flat pool. Only arities 1-3 are needed by the
# registered primitive set.
make a function called sbe_arg_types_has_any takes arg_types returns yes
let i = 0
let n = to_num(list_len(arg_types))
while i < n do
if arg_types[i] == "any" then
return true
end
let i = i + 1
end
return false
end
make a function called sbe_resolve_any_types takes arg_types, concrete returns out
let out = []
let i = 0
let n = to_num(list_len(arg_types))
while i < n do
if arg_types[i] == "any" then
let out = list_push(out, concrete)
else
let out = list_push(out, arg_types[i])
end
let i = i + 1
end
return out
end
# A call with more than one "any" position (e.g. cond(test, a, b)'s two
# branches) must have EVERY "any" position resolve to the SAME concrete
# type together, not independently -- resolving them independently once
# let a candidate's two branches be different types (say int and bool),
# which is exactly how a single-example-derived type tag went stale on a
# later example with a different test outcome, crashing a downstream
# comparison with a real "type error in cmp" (confirmed directly while
# building the first_exceeding worked example). Only "any" itself is
# ever ambiguous this way -- every other declared type is fixed
# regardless of value, so this loop is skipped entirely (zero behavior
# change) for every primitive that doesn't use "any".
#
# `target_size`/`size` throughout this file means each registered
# primitive's own declared COST (primitive_registry.patlang's
# pr_register 5th arg), not a flat "1 call = 1 unit" node count -- found
# and fixed as a real latent bug (GitHub issue #71's closing
# investigation, self_hosting/lib/fact_relaxation_synthesis.patlang):
# most primitives happen to cost 1, but index_of_from costs 2 and
# tcp_connect costs 5, and this function used to hardcode `rem =
# target_size - 1` regardless, silently ignoring registered cost
# whenever it wasn't 1 -- "smallest wins" was really "fewest AST nodes
# wins". `prim_cost` (the calling primitive's own registered cost,
# looked up once by the caller) replaces that hardcoded 1.
make a function called sbe_build_calls takes prim, arg_types, arg_contracts, target_size, index, prim_cost returns out
if sbe_arg_types_has_any(arg_types) then
let out = []
let types = sbe_concrete_types()
let t = 0
let tn = to_num(list_len(types))
while t < tn do
let resolved = sbe_resolve_any_types(arg_types, types[t])
let out = sbe_list_concat(out, sbe_build_calls(prim, resolved, arg_contracts, target_size, index, prim_cost))
let t = t + 1
end
return out
end
let out = []
let rem = target_size - prim_cost
let arity = to_num(list_len(arg_types))
if arity == 1 then
if rem >= 1 then
let group = sbe_index_lookup_filtered(index, rem, arg_types[0], arg_contracts[0])
let i = 0
let n = to_num(list_len(group))
while i < n do
let out = list_push(out, ["Call", prim, [group[i]]])
let i = i + 1
end
end
return out
end
if arity == 2 then
let a = 1
while a <= rem - 1 do
let b = rem - a
let ga = sbe_index_lookup_filtered(index, a, arg_types[0], arg_contracts[0])
let gb = sbe_index_lookup_filtered(index, b, arg_types[1], arg_contracts[1])
let i = 0
let ni = to_num(list_len(ga))
while i < ni do
let j = 0
let nj = to_num(list_len(gb))
while j < nj do
let out = list_push(out, ["Call", prim, [ga[i], gb[j]]])
let j = j + 1
end
let i = i + 1
end
let a = a + 1
end
return out
end
if arity == 3 then
let a = 1
while a <= rem - 2 do
let b = 1
while b <= rem - a - 1 do
let c = rem - a - b
let ga = sbe_index_lookup_filtered(index, a, arg_types[0], arg_contracts[0])
let gb = sbe_index_lookup_filtered(index, b, arg_types[1], arg_contracts[1])
let gc = sbe_index_lookup_filtered(index, c, arg_types[2], arg_contracts[2])
let i = 0
let ni = to_num(list_len(ga))
while i < ni do
let j = 0
let nj = to_num(list_len(gb))
while j < nj do
let k = 0
let nk = to_num(list_len(gc))
while k < nk do
let out = list_push(out, ["Call", prim, [ga[i], gb[j], gc[k]]])
let k = k + 1
end
let j = j + 1
end
let i = i + 1
end
let b = b + 1
end
let a = a + 1
end
return out
end
if arity == 4 then
let a = 1
while a <= rem - 3 do
let b = 1
while b <= rem - a - 2 do
let c = 1
while c <= rem - a - b - 1 do
let d = rem - a - b - c
let ga = sbe_index_lookup_filtered(index, a, arg_types[0], arg_contracts[0])
let gb = sbe_index_lookup_filtered(index, b, arg_types[1], arg_contracts[1])
let gc = sbe_index_lookup_filtered(index, c, arg_types[2], arg_contracts[2])
let gd = sbe_index_lookup_filtered(index, d, arg_types[3], arg_contracts[3])
let i = 0
let ni = to_num(list_len(ga))
while i < ni do
let j = 0
let nj = to_num(list_len(gb))
while j < nj do
let k = 0
let nk = to_num(list_len(gc))
while k < nk do
let l = 0
let nl = to_num(list_len(gd))
while l < nl do
let out = list_push(out, ["Call", prim, [ga[i], gb[j], gc[k], gd[l]]])
let l = l + 1
end
let k = k + 1
end
let j = j + 1
end
let i = i + 1
end
let c = c + 1
end
let b = b + 1
end
let a = a + 1
end
return out
end
return out
end
make a function called sbe_matches_all takes node, examples, registry returns ok
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let result = sbe_eval(node, ex[0], registry)
if result[0] == false then
return false
end
if result[1] != ex[1] then
return false
end
let i = i + 1
end
return true
end
# Observational-equivalence key: two candidates that produce the exact
# same [ok, value] outcome across every example are interchangeable for
# search purposes -- keeping only the first (smallest) one found is the
# same pruning classic enumerative synthesis engines use to stay
# tractable.
make a function called sbe_output_key takes node, examples, registry returns key
let key = sb_new()
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let result = sbe_eval(node, ex[0], registry)
if result[0] then
sb_push(key, "1:" + ("" + result[1]))
else
sb_push(key, "0")
end
sb_push(key, "|")
let i = i + 1
end
return sb_str(key)
end
make a function called sbe_list_concat takes a, b returns out
let out = a
let i = 0
let n = to_num(list_len(b))
while i < n do
let out = list_push(out, b[i])
let i = i + 1
end
return out
end
make a function called sbe_seed_leaves takes input_names, const_values returns out
let out = []
let i = 0
let n = to_num(list_len(input_names))
while i < n do
let out = list_push(out, ["Input", input_names[i]])
let i = i + 1
end
let i = 0
let n = to_num(list_len(const_values))
while i < n do
let out = list_push(out, ["Const", const_values[i]])
let i = i + 1
end
return out
end
# A small, DOCUMENTED curated constant pool, not the full 0-255 byte range:
# the plan's original "0-255" idea would blow up the level-2 combinatorics
# (every Call argument slot drawn from this pool) to hundreds of millions
# of candidates for a 2-3 argument primitive. Covers the separators/counts
# actually needed by ASCII text parsing (CR/LF/space/tab, and small
# offsets like "one past a delimiter"); callers needing a different pool
# (e.g. a specific separator string) pass it via `extra_consts`.
make a function called sbe_default_int_consts returns cs
return [0, 1, 2, 3, 9, 10, 13, 32]
end
# ---- parallel candidate evaluation ----
#
# Each candidate's evaluation (does it match every example? what's its
# observational-equivalence key? what type/value does it produce?) is
# pure and independent of every other candidate's -- the confirmed real
# bottleneck (measured directly: ~250,000 independent evaluations at one
# level of the first_exceeding search, see the site page's worked
# example) is exactly the shape parallel_map (rust-runtime/src/ir/
# interpreter.rs's real-OS-thread map, not a fiber) is for. This worker
# is a plain top-level function, not a closure, because parallel_map
# calls it as `name(item)` on a fresh Interpreter per thread with no
# access to synthesize_from_examples's own locals -- examples/registry/
# sample_bindings are fetched from __vars instead, which PatLang's
# object store already guarantees is shared across every OS thread
# (confirmed: it's a single process-wide Mutex-protected map, not
# per-interpreter state). The SAME worker is used for the sequential
# fallback below max_size threshold too, so both paths share one
# implementation and can never silently diverge in behavior.
make a function called sbe_eval_candidate_worker takes node returns result
let examples = get("__vars", "sbe_par_examples")
let registry = get("__vars", "sbe_par_registry")
let sample_bindings = get("__vars", "sbe_par_sample_bindings")
let ok = sbe_matches_all(node, examples, registry)
let key = sbe_output_key(node, examples, registry)
let typed = sbe_wrap(node, registry, sample_bindings)
return [ok, key, typed[2], typed[3]]
end
# Below this many candidates, thread-spawn overhead would cost more than
# it saves (confirmed: sizes 2-8 typically have dozens to low hundreds of
# candidates and already finish in well under a second sequentially).
make a function called sbe_parallel_threshold returns n
return 300
end
# parallel_map spawns one real OS thread PER ITEM it's given (rust-
# runtime/src/ir/interpreter.rs:346-361's std::thread::scope loop) --
# fine for a bounded list, but a candidate list at size 14+ can run into
# the tens of thousands, and spawning that many threads AT ONCE causes
# real OS-level scheduling contention (confirmed directly: the whole
# machine, not just this process, became sluggish -- not a memory or
# per-process CPU symptom, a thread-count one). Fixed by chunking:
# split the candidate list into a small, FIXED number of chunks
# (matching real core count, not the candidate count), and parallel_map
# over the CHUNKS -- each chunk's own candidates are evaluated
# sequentially, within that one thread, by sbe_eval_candidate_chunk_worker.
make a function called sbe_parallel_chunk_count returns n
return 20
end
make a function called sbe_chunk_list takes items, num_chunks returns chunks
let n = to_num(list_len(items))
let chunks = []
if n == 0 then
return chunks
end
let chunk_size = to_num(floor((n + num_chunks - 1) / num_chunks))
if chunk_size < 1 then
let chunk_size = 1
end
let i = 0
while i < n do
let stop = i + chunk_size
if stop > n then
let stop = n
end
let chunk = []
let j = i
while j < stop do
let chunk = list_push(chunk, items[j])
let j = j + 1
end
let chunks = list_push(chunks, chunk)
let i = stop
end
return chunks
end
make a function called sbe_eval_candidate_chunk_worker takes chunk returns results
let results = []
let i = 0
let n = to_num(list_len(chunk))
while i < n do
let results = list_push(results, sbe_eval_candidate_worker(chunk[i]))
let i = i + 1
end
return results
end
make a function called sbe_evaluate_candidates takes candidates, examples, registry, sample_bindings returns results
set_var("sbe_par_examples", examples)
set_var("sbe_par_registry", registry)
set_var("sbe_par_sample_bindings", sample_bindings)
let cn = to_num(list_len(candidates))
if cn > sbe_parallel_threshold() then
let chunks = sbe_chunk_list(candidates, sbe_parallel_chunk_count())
let chunk_results = parallel_map(chunks, "sbe_eval_candidate_chunk_worker")
# Flatten in order -- parallel_map preserves input order, and each
# chunk's own results are already in-order (sequential within it),
# so a straight concatenation reconstructs candidates' original order.
let results = []
let k = 0
let kn = to_num(list_len(chunk_results))
while k < kn do
let results = sbe_list_concat(results, chunk_results[k])
let k = k + 1
end
return results
end
let results = []
let c = 0
while c < cn do
let results = list_push(results, sbe_eval_candidate_worker(candidates[c]))
let c = c + 1
end
return results
end
# ---- the bottom-up search ----
#
# Returns ["OK", ast] for the smallest AST (by node count) that reproduces
# every example exactly, searched in strictly increasing size order so the
# first match found IS the smallest, or ["ERR", msg] if none exists up to
# max_size.
# ---- diagnostics ----
#
# The exponential blow-up measured on a flat, non-decomposed search (see
# the plan/session notes on replace_in_text) and the "constant trap"/
# "algebraic coincidence" pitfalls found repeatedly across this session's
# demos (after_space, tail_after, inner_text -- always because too few
# examples let a smaller, wrong candidate through) are the SAME kind of
# signal in both directions: the search itself already has the data to
# tell a BDD author "this spec needs splitting" (sustained fast pool
# growth) or "this spec needs another example" (more than one
# structurally different, equally-minimal candidate satisfies it) --
# rather than that only ever being noticed after the fact by a human
# staring at a suspicious-looking AST. These notes are advisory only
# (appended as a 3rd list element every existing caller already ignores,
# since none of them look past result[0]/result[1]).
make a function called sbe_growth_note takes size, ratio returns note
return "search pool grew " + to_fixed(ratio, 1) + "x at size " + size + " (sustained fast growth) -- if this gets slow, consider decomposing the target into smaller, independently-specified composites (see how after_space/take_before/take_after/splice were split out of replace_in_text)"
end
make a function called sbe_ambiguity_note takes alt_count, size returns note
return "" + alt_count + " other structurally different candidate(s) of the same minimal size (" + size + ") also satisfy every given example -- if the intended behavior is more specific than what's shown, add a disambiguating example (the same fix that ruled out after_space's substr-clamp shortcut and inner_text's reused-length shortcut)"
end
make a function called synthesize_from_examples takes examples, input_names, extra_consts, registry, primitive_names, max_size returns result
let consts = sbe_list_concat(sbe_default_int_consts(), extra_consts)
let sample_bindings = examples[0][0]
let leaves = sbe_seed_leaves(input_names, consts)
let index = sbe_index_new()
let seen = new("Dict", "sbe_seen_" + pr_next_id())
let pool_count = 0
let notes = []
let high_growth_streak = 0
let winner = ["Const", ""]
let found_match = false
let alt_count = 0
let i = 0
let n = to_num(list_len(leaves))
while i < n do
let node = leaves[i]
if sbe_matches_all(node, examples, registry) then
if found_match then
let alt_count = alt_count + 1
else
let found_match = true
let winner = node
end
end
let key = sbe_output_key(node, examples, registry)
if not get(seen, key) then
send(seen, "set", key, true)
sbe_index_add(index, sbe_wrap(node, registry, sample_bindings))
let pool_count = pool_count + 1
end
let i = i + 1
end
if found_match then
if alt_count > 0 then
let notes = list_push(notes, sbe_ambiguity_note(alt_count, 1))
end
return ["OK", winner, notes]
end
let size = 2
while size <= max_size do
print("synthesize_from_examples: size=" + size + " pool=" + pool_count + " at " + now_ms())
let pool_before_level = pool_count
# Accumulate this level's newly-accepted candidates in plain LOCAL
# lists, one per runtime type, grouped by hand rather than through
# the Dict-backed index -- every candidate this level shares the same
# `size`, so each of these lists becomes exactly one brand-new bucket
# merged into the index ONCE at the end of the level (via
# sbe_index_set_bucket), instead of once per candidate. A uniquely-
# held local list's list_push is a genuine O(1) amortized append;
# reading a bucket back out of the index mid-level and pushing onto
# THAT would alias its stored Arc and force a full deep clone on
# every single push (measured directly: doing it that way made this
# search slower than the flat scan it was meant to replace).
let level_int = []
let level_string = []
let level_bool = []
let level_list = []
let winner = ["Const", ""]
let found_match = false
let alt_count = 0
let p = 0
let pn = to_num(list_len(primitive_names))
while p < pn do
let prim = primitive_names[p]
let entry = pr_lookup(registry, prim)
if entry then
let arg_types = entry[5]
let arg_contracts = entry[7]
let prim_cost = to_num(entry[3])
let candidates = sbe_build_calls(prim, arg_types, arg_contracts, size, index, prim_cost)
let cn = to_num(list_len(candidates))
let results = sbe_evaluate_candidates(candidates, examples, registry, sample_bindings)
# Sequential reduce pass -- cheap bookkeeping only, since the
# expensive per-candidate work already happened above (in
# parallel, once cn is large enough). Iterated by index so the
# exact same logic serves both the parallel and sequential paths
# from sbe_evaluate_candidates, and so "first match in original
# order wins" stays deterministic regardless of which path ran.
let c = 0
while c < cn do
let node = candidates[c]
let r = results[c]
let ok = r[0]
let key = r[1]
let ty = r[2]
let value = r[3]
if ok then
if found_match then
let alt_count = alt_count + 1
else
let found_match = true
let winner = node
end
end
let already = get(seen, key)
if not already then
send(seen, "set", key, true)
let typed = [node, size, ty, value]
if ty == "int" then
let level_int = list_push(level_int, typed)
else
if ty == "string" then
let level_string = list_push(level_string, typed)
else
if ty == "bool" then
let level_bool = list_push(level_bool, typed)
else
if ty == "list" then
let level_list = list_push(level_list, typed)
end
end
end
end
let pool_count = pool_count + 1
end
let c = c + 1
end
end
let p = p + 1
end
if to_num(list_len(level_int)) > 0 then
sbe_index_set_bucket(index, "int", size, level_int)
end
if to_num(list_len(level_string)) > 0 then
sbe_index_set_bucket(index, "string", size, level_string)
end
if to_num(list_len(level_bool)) > 0 then
sbe_index_set_bucket(index, "bool", size, level_bool)
end
if to_num(list_len(level_list)) > 0 then
sbe_index_set_bucket(index, "list", size, level_list)
end
let evict_size = size - sbe_window_size()
if evict_size >= 2 then
sbe_evict_size(index, evict_size)
end
if pool_before_level > 0 then
let ratio = pool_count / pool_before_level
if ratio > 2.5 then
let high_growth_streak = high_growth_streak + 1
if high_growth_streak >= 2 then
let notes = list_push(notes, sbe_growth_note(size, ratio))
end
else
let high_growth_streak = 0
end
end
if found_match then
if alt_count > 0 then
let notes = list_push(notes, sbe_ambiguity_note(alt_count, size))
end
return ["OK", winner, notes]
end
let size = size + 1
end
let notes = list_push(notes, "reached max_size (" + max_size + ") without a match -- consider decomposing the target into smaller, independently-specified composites (see how after_space/take_before/take_after/splice were split out of replace_in_text) rather than raising max_size further")
return ["ERR", "no candidate up to size " + max_size, notes]
end
# ---- second mode: decision-list synthesis ----
#
# A finite literal-input -> literal-output mapping (e.g. "/health" ->
# "OK") isn't naturally reachable by expression composition alone -- this
# is a deliberately different, much simpler technique (build a chain of
# equality-guarded branches straight from the example pairs, ending in a
# default), not a variant of the enumerator above.
make a function called synthesize_lookup_from_examples takes input_name, examples, default_value returns ast
let node = ["Const", default_value]
let i = to_num(list_len(examples)) - 1
while i >= 0 do
let ex = examples[i]
let cond = ["Call", "str_eq", [["Input", input_name], ["Const", ex[0]]]]
let node = ["If", cond, ["Const", ex[1]], node]
let i = i - 1
end
return node
end
# ---- multi-language emission ----
#
# Walks a winning (non-decision-list) AST once, looking up each Call
# node's primitive/composite name in the registry's per-language snippet
# dict and substituting recursively-emitted argument code into the
# template's {0}/{1}/... placeholders. Errors BY NAME on a primitive with
# no snippet registered for the requested language -- matching
# self_hosting/lib/transpile_ruby.patlang's own convention of a clear
# ["Err", msg] over silently-broken output -- rather than guessing.
# Deliberately does not handle "If" nodes (decision-list ASTs use their
# own dedicated PatLang-only emitter below, since PatLang's `if` is a
# statement, not an expression -- there is no single-expression rendering
# to fall back to for that shape in this language).
make a function called sbe_quote_string takes s returns text
let out = sb_new()
sb_push(out, "\"")
let i = 0
let n = s.length
while i < n do
let c = char_code(s, i)
if c == 92 then
sb_push(out, "\\\\")
else
if c == 34 then
sb_push(out, "\\\"")
else
if c == 10 then
sb_push(out, "\\n")
else
if c == 13 then
sb_push(out, "\\r")
else
sb_push(out, s[i])
end
end
end
end
let i = i + 1
end
sb_push(out, "\"")
return sb_str(out)
end
make a function called sbe_emit_const takes v returns text
let ty = type_of(v)
if ty == "string" then
return sbe_quote_string(v)
end
if ty == "bool" then
if v then
return "true"
end
return "false"
end
return "" + v
end
make a function called sbe_replace_all takes s, needle, replacement returns out
let out = sb_new()
let i = 0
let nlen = needle.length
let slen = s.length
while i < slen do
if (nlen > 0) and (i <= slen - nlen) and (substr(s, i, nlen) == needle) then
sb_push(out, replacement)
let i = i + nlen
else
sb_push(out, s[i])
let i = i + 1
end
end
return sb_str(out)
end
make a function called sbe_fill_template takes tmpl, arg_texts returns out
let out = tmpl
let i = 0
let n = to_num(list_len(arg_texts))
while i < n do
let placeholder = "{" + i + "}"
let out = sbe_replace_all(out, placeholder, arg_texts[i])
let i = i + 1
end
return out
end
make a function called emit_ast takes node, lang, registry returns result
let tag = node[0]
if tag == "Const" then
return ["OK", sbe_emit_const(node[1])]
end
if tag == "Input" then
return ["OK", node[1]]
end
if tag == "Call" then
let prim = node[1]
let arg_nodes = node[2]
let tmpl = pr_snippet(registry, prim, lang)
if tmpl == "" then
return ["ERR", "no \"" + lang + "\" snippet registered for \"" + prim + "\""]
end
let arg_texts = []
let i = 0
let n = to_num(list_len(arg_nodes))
while i < n do
let sub = emit_ast(arg_nodes[i], lang, registry)
if sub[0] != "OK" then
return sub
end
let arg_texts = list_push(arg_texts, sub[1])
let i = i + 1
end
return ["OK", sbe_fill_template(tmpl, arg_texts)]
end
return ["ERR", "emit_ast: unsupported node tag \"" + tag + "\" for expression emission (decision-list ASTs use emit_decision_list_patlang)"]
end
# Full function-definition text for a plain expression-bodied composite
# (crlf/first_line/es_contains-shaped -- no branching), in PatLang.
make a function called emit_function_def_patlang takes name, param_names, node, registry returns result
let body = emit_ast(node, "patlang", registry)
if body[0] != "OK" then
return body
end
let params = sbe_join_comma(param_names)
let text = "make a function called " + name + " takes " + params + " returns result\n let result = " + body[1] + "\n return result\nend\n"
if to_num(list_len(param_names)) == 0 then
let text = "make a function called " + name + " returns result\n let result = " + body[1] + "\n return result\nend\n"
end
return ["OK", text]
end
make a function called sbe_join_comma takes items returns out
let out = sb_new()
let i = 0
let n = to_num(list_len(items))
while i < n do
if i > 0 then
sb_push(out, ", ")
end
sb_push(out, items[i])
let i = i + 1
end
return sb_str(out)
end
# Decision-list ASTs (synthesize_lookup_from_examples's output) are a
# strictly right-leaning chain of ["If", cond, then, rest] nodes ending in
# a default -- rendered directly as PatLang if/elif/.../else statements
# (CLAUDE.md's own convention for this repo: elif, never nested else-if),
# not through the generic expression emitter above.
make a function called emit_decision_list_patlang takes node, registry returns text
let out = sb_new()
let cur = node
let first = true
while cur[0] == "If" do
let cond_r = emit_ast(cur[1], "patlang", registry)
let then_r = emit_ast(cur[2], "patlang", registry)
if first then
sb_push(out, "if " + cond_r[1] + " then\n")
let first = false
else
sb_push(out, "elif " + cond_r[1] + " then\n")
end
sb_push(out, " return " + then_r[1] + "\n")
let cur = cur[3]
end
let default_r = emit_ast(cur, "patlang", registry)
sb_push(out, " else\n return " + default_r[1] + "\n end\n")
return sb_str(out)
end
make a function called emit_decision_function_patlang takes name, param_name, node, registry returns text
return "make a function called " + name + " takes " + param_name + " returns result\n " + emit_decision_list_patlang(node, registry) + "end\n"
end
# ---- composites become registry citizens ----
#
# Once synthesize_from_examples/synthesize_lookup_from_examples finds a
# winning AST, registering it back into the SAME registry under `name`
# means a LATER, larger search can call it as an ordinary primitive
# (arity = param count), and its call-site rendering is available in
# every language the registry already knows about -- call syntax
# `name(args...)` is uniform across PatLang/Ruby/Python, so no per-
# language body re-derivation is needed just to make the composite
# CALLABLE; only actually emitting its own definition (emit_function_def_
# patlang / emit_decision_function_patlang above) needs the AST itself,
# which register_composite stores alongside the call template.
make a function called register_composite takes registry, name, ast, param_names, arg_types, cost returns done
let snippets = pr_new_snippets()
let placeholders = []
let i = 0
let n = to_num(list_len(param_names))
while i < n do
let placeholders = list_push(placeholders, "{" + i + "}")
let i = i + 1
end
let call_text = name + "(" + sbe_join_comma(placeholders) + ")"
pr_set_snippet(snippets, "patlang", call_text)
pr_set_snippet(snippets, "ruby", call_text)
pr_set_snippet(snippets, "python", call_text)
# Composites are registered under ret_type "any" (rather than trying to
# infer a precise one here without access to the examples that proved
# them) and with no extra arg_contracts beyond their type tags -- this
# keeps register_composite's own signature unchanged for every existing
# caller. Being "any" only means pr_names_for_ret_type always offers a
# composite as a candidate for any requested type; it never causes one
# to be wrongly excluded, so this is a safe, low-precision default, not
# a correctness gap.
let arg_contracts = []
let i = 0
let n = to_num(list_len(arg_types))
while i < n do
let arg_contracts = list_push(arg_contracts, "")
let i = i + 1
end
send(registry, "set", name, ["composite", [ast, param_names], to_num(list_len(param_names)), cost, snippets, arg_types, "any", arg_contracts])
let idx = get(registry, "__by_ret_type__")
if not idx then
let idx = new("Dict", "pr_by_ret_type_" + pr_next_id())
send(registry, "set", "__by_ret_type__", idx)
end
let existing = get(idx, "any")
if existing then
send(idx, "set", "any", list_push(existing, name))
else
send(idx, "set", "any", [name])
end
return true
end
# Scans the index for a node whose value (under sample_bindings/
# example 0, the same value sbe_index_add already stored) exactly
# equals target_value, smallest size first -- so a witness-found match
# is never larger than one already sitting in the forward pool.
make a function called bidi_index_scan_by_value takes index, ty, target_value, max_size_so_far returns node
let s = 1
while s <= max_size_so_far do
let bucket = sbe_index_lookup(index, s, ty)
let i = 0
let n = to_num(list_len(bucket))
while i < n do
if bucket[i][3] == target_value then
return bucket[i][0]
end
let i = i + 1
end
let s = s + 1
end
return false
end
# concat(a, b) = target, split at position k: a = target[0:k], b =
# target[k:]. Looks up `a` FIRST (by its example-0 value), then -- only
# if found -- derives what `b` must be for EVERY example from that
# specific node's own per-example values (never assuming example 0's
# split point transfers literally to other examples, since target
# strings vary in length across examples), and looks up `b` the same
# way. Both sides must already exist in the forward index for this to
# fire -- Phase 1 doesn't hand back an open sub-goal for further
# recursive decomposition, it only reports an immediate meet.
make a function called bidi_try_concat_split takes examples, index, registry, max_size_so_far, k returns result
let t0 = examples[0][1]
let a0 = substr(t0, 0, k)
let node_a = bidi_index_scan_by_value(index, "string", a0, max_size_so_far)
if node_a then
let ok = true
let b_values = []
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let av = sbe_eval(node_a, ex[0], registry)
let ti = ex[1]
if av[0] == false then
let ok = false
else
let al = av[1].length
if (al > ti.length) or (substr(ti, 0, al) != av[1]) then
let ok = false
else
let b_values = list_push(b_values, substr(ti, al, ti.length - al))
end
end
let i = i + 1
end
if ok then
let node_b = bidi_index_scan_by_value(index, "string", b_values[0], max_size_so_far)
if node_b then
let bok = true
let j = 0
let jn = to_num(list_len(examples))
while j < jn do
let bv = sbe_eval(node_b, examples[j][0], registry)
if (bv[0] == false) or (bv[1] != b_values[j]) then
let bok = false
end
let j = j + 1
end
if bok then
return ["OK", ["Call", "concat", [node_a, node_b]]]
end
end
end
end
return ["ERR"]
end
make a function called bidi_try_concat takes examples, index, registry, max_size_so_far returns result
let kn = examples[0][1].length
let k = 0
while k <= kn do
let r = bidi_try_concat_split(examples, index, registry, max_size_so_far, k)
if r[0] == "OK" then
return r
end
let k = k + 1
end
return ["ERR"]
end
# add(v, other) = target => other = target - v, and sub(v, other) =
# target => other = v - target -- both checked against the SAME scan
# over already-indexed int candidates for `v`, since both directions
# are worth trying per candidate at negligible extra cost.
make a function called bidi_try_arith takes examples, index, registry, max_size_so_far returns result
let s = 1
while s <= max_size_so_far do
let bucket = sbe_index_lookup(index, s, "int")
let bi = 0
let bn = to_num(list_len(bucket))
while bi < bn do
let node_v = bucket[bi][0]
let n = to_num(list_len(examples))
let ok_add = true
let other_add = []
let i = 0
while i < n do
let ex = examples[i]
let vv = sbe_eval(node_v, ex[0], registry)
if vv[0] == false then
let ok_add = false
else
let other_add = list_push(other_add, ex[1] - vv[1])
end
let i = i + 1
end
if ok_add then
let node_other = bidi_index_scan_by_value(index, "int", other_add[0], max_size_so_far)
if node_other then
let verify_ok = true
let j = 0
while j < n do
let ov = sbe_eval(node_other, examples[j][0], registry)
if (ov[0] == false) or (ov[1] != other_add[j]) then
let verify_ok = false
end
let j = j + 1
end
if verify_ok then
return ["OK", ["Call", "add", [node_v, node_other]]]
end
end
end
let ok_sub = true
let other_sub = []
let i2 = 0
while i2 < n do
let ex = examples[i2]
let vv = sbe_eval(node_v, ex[0], registry)
if vv[0] == false then
let ok_sub = false
else
let other_sub = list_push(other_sub, vv[1] - ex[1])
end
let i2 = i2 + 1
end
if ok_sub then
let node_other2 = bidi_index_scan_by_value(index, "int", other_sub[0], max_size_so_far)
if node_other2 then
let verify_ok2 = true
let j2 = 0
while j2 < n do
let ov2 = sbe_eval(node_other2, examples[j2][0], registry)
if (ov2[0] == false) or (ov2[1] != other_sub[j2]) then
let verify_ok2 = false
end
let j2 = j2 + 1
end
if verify_ok2 then
return ["OK", ["Call", "sub", [node_v, node_other2]]]
end
end
end
let bi = bi + 1
end
let s = s + 1
end
return ["ERR"]
end
# ---- Phase 3: range witnesses for gt/geq/eq_int ----
#
# A boolean target from a comparison doesn't pin its two arguments to
# single values the way concat's split or add/sub's two-sum inversion
# do -- gt(a,b)=true only pins the RELATION between a and b, and the
# set of (a,b) pairs satisfying a relation is unbounded in general (any
# a>b at all). The useful, bounded move: scan pairs of ALREADY forward-
# built int candidates directly (not inventing new ones) and check
# whether the relation already holds across every example -- a
# filtering pass over existing work, exactly like concat/arith's
# witnesses, just checking a relation instead of deriving one exact
# target value per side. Smallest-total-size-first (outer loop by size)
# so a match here is never larger than one plain forward search over
# gt/geq/eq_int at the same level would eventually find -- this witness
# doesn't skip ahead of when the forward loop would naturally construct
# the same expression (their combined size is fixed either way), it
# just reaches it via a cheaper existing-pool scan instead of sbe_
# build_calls's own combinatorial arg-type-and-contract generation.
make a function called bidi_relation_holds takes rel, av, bv returns yes
if rel == "gt" then
return av > bv
end
if rel == "geq" then
return av >= bv
end
if rel == "eq_int" then
return av == bv
end
return false
end
make a function called bidi_try_range takes examples, index, registry, max_size_so_far, primitive_names returns result
let rels = []
if bidi_list_contains(primitive_names, "gt") then
let rels = list_push(rels, "gt")
end
if bidi_list_contains(primitive_names, "geq") then
let rels = list_push(rels, "geq")
end
if bidi_list_contains(primitive_names, "eq_int") then
let rels = list_push(rels, "eq_int")
end
if to_num(list_len(rels)) == 0 then
return ["ERR"]
end
let sa = 1
while sa <= max_size_so_far do
let bucket_a = sbe_index_lookup(index, sa, "int")
let ai = 0
let an = to_num(list_len(bucket_a))
while ai < an do
let node_a = bucket_a[ai][0]
let sb = 1
while sb <= max_size_so_far do
let bucket_b = sbe_index_lookup(index, sb, "int")
let bi = 0
let bn = to_num(list_len(bucket_b))
while bi < bn do
let node_b = bucket_b[bi][0]
let ri = 0
let rn = to_num(list_len(rels))
while ri < rn do
let rel = rels[ri]
let ok = true
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let av = sbe_eval(node_a, ex[0], registry)
let bv = sbe_eval(node_b, ex[0], registry)
if (av[0] == false) or (bv[0] == false) then
let ok = false
else
if bidi_relation_holds(rel, av[1], bv[1]) != ex[1] then
let ok = false
end
end
let i = i + 1
end
if ok then
return ["OK", ["Call", rel, [node_a, node_b]]]
end
let ri = ri + 1
end
let bi = bi + 1
end
let sb = sb + 1
end
let ai = ai + 1
end
let sa = sa + 1
end
return ["ERR"]
end
# ---- cond as a direct scan witness, not partition-and-recurse ----
#
# The original bidi_try_cond commits to a COMPLETE partition of the
# examples upfront, then runs THREE full recursive syntheses (a, b,
# test) before ever checking whether the combination holds together --
# most of the 2^n-2 candidate partitions are wrong, but they don't fail
# fast: they succeed locally on their own subset and waste a full
# expensive sub-search before the outer verification catches it.
# Measured directly on the real 8-example case: 55s average per
# recursive sub-search, with no fast-fail path for a bad guess.
#
# This is the constraint-propagation alternative: `test`/`a`/`b` are
# never separately synthesized at all -- they're read directly off the
# SAME shared, already-being-built forward index every OTHER witness in
# this file already scans (bidi_try_concat/arith/range), and checked
# for per-example consistency using their ALREADY-CACHED behavior
# (sbe_eval against each example's own bindings -- a plain value
# lookup, not a new synthesis). A bad (test,a,b) triple is rejected in
# O(examples) cheap comparisons, not after a full recursive solve. The
# "local world state" is exactly this: per-example, what value has this
# specific candidate ALREADY produced -- never a combinatorial subset
# of facts (that's the STRIPS/GOAP shape issue #71 already ruled out
# for this problem), just one cached value per example per candidate.
#
# Tried directly, not just reasoned about: the constraint-propagation
# fix is real (validated on a small ambiguous case -- correct minimal
# answer, ~700ms, matching Phase 3's own result). But wiring it into
# bidi_witness_pass (tried every level, like concat/arith/range) made
# the real first_exceeding case WORSE than the partition-based
# bidi_try_cond, not better: this scan is a TRIPLE-nested loop over
# (a,b,test) candidate pools -- cubic in pool size -- and this domain's
# `any`-typed pools are already large (the same combinatorial driver
# behind issue #73/#69). It genuinely exhausted the interpreter's 8GB
# memory cap at size 8 alone on the 5-example case, where partition-
# based cond finds the answer in ~29s total. Kept here as a documented,
# available alternative (NOT wired into bidi_witness_pass's default
# flow) -- a real, different tool for a domain with small-to-modest
# per-level pools, not a strict improvement for one with large ones. A
# genuinely better version would need value-INDEXED lookups for the
# third argument (given test+a, look up the exact node matching the
# remaining examples' required values directly, the same trick concat/
# arith's witnesses already use) instead of a brute nested scan over
# every candidate -- real further engineering, not attempted here.
make a function called bidi_try_cond_scan takes examples, index, registry, max_size_so_far, target_type returns result
let sa = 1
while sa <= max_size_so_far do
let bucket_a = sbe_index_lookup(index, sa, target_type)
let ai = 0
let an = to_num(list_len(bucket_a))
while ai < an do
let node_a = bucket_a[ai][0]
let sb = 1
while sb <= max_size_so_far do
let bucket_b = sbe_index_lookup(index, sb, target_type)
let bi = 0
let bn = to_num(list_len(bucket_b))
while bi < bn do
let node_b = bucket_b[bi][0]
if node_a != node_b then
let st = 1
while st <= max_size_so_far do
let bucket_t = sbe_index_lookup(index, st, "bool")
let ti = 0
let tn = to_num(list_len(bucket_t))
while ti < tn do
let node_t = bucket_t[ti][0]
let ok = true
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let tv = sbe_eval(node_t, ex[0], registry)
if tv[0] == false then
let ok = false
else
let chosen = node_a
if tv[1] == false then
let chosen = node_b
end
let cv = sbe_eval(chosen, ex[0], registry)
if (cv[0] == false) or (cv[1] != ex[1]) then
let ok = false
end
end
let i = i + 1
end
if ok then
return ["OK", ["Call", "cond", [node_t, node_a, node_b]]]
end
let ti = ti + 1
end
let st = st + 1
end
end
let bi = bi + 1
end
let sb = sb + 1
end
let ai = ai + 1
end
let sa = sa + 1
end
return ["ERR"]
end
make a function called bidi_witness_pass takes examples, index, registry, max_size_so_far, target_type, primitive_names returns result
if bidi_list_contains(primitive_names, "cond") then
let cr = bidi_try_cond_combined(examples, index, registry, max_size_so_far, target_type)
if cr[0] == "OK" then
return cr
end
end
if target_type == "string" then
return bidi_try_concat(examples, index, registry, max_size_so_far)
end
if target_type == "int" then
return bidi_try_arith(examples, index, registry, max_size_so_far)
end
if target_type == "bool" then
return bidi_try_range(examples, index, registry, max_size_so_far, primitive_names)
end
return ["ERR"]
end
# ---- Phase 2: cond's disjunctive witness ----
#
# cond(test, a, b) = target doesn't have ONE inverse the way concat/add
# do -- it has two, and they don't compose the same way (a split always
# names exactly one pair of sub-goals; a branch could be either of two
# DIFFERENT sub-expressions, and which examples belong to which branch
# isn't known in advance). The witness here: try every way of
# partitioning the examples into two non-empty groups, and for each
# partition, search independently for (a) an expression correct on the
# "true" group, (b) an expression correct on the "false" group, and
# (c) a boolean expression that is true on the "true" group and false
# on the "false" group -- reusing the SAME recursive search (forward +
# Phase 1 witnesses) for all three, not a separate mechanism. Only
# succeeds if all three sub-searches succeed AND the assembled
# cond(test,a,b) verifies against every original example (a partition
# guess can be internally consistent per-branch yet still wrong overall
# if the "test" that separates them doesn't generalize the same way the
# real domain does -- sbe_matches_all is the final, unconditional
# check, same as everywhere else in this codebase).
#
# Bounded by 2^n - 2 partitions for n examples (every non-empty,
# non-full split; no attempt to dedupe a partition against its A/B-
# swapped mirror, which just tries the same work twice, not more of it)
# -- fine for the single-digit example counts this codebase's own
# demos use, not attempted for large n. depth caps recursion (each
# sub-search can itself try to build a cond via its own boolean-test
# search), since a boolean sub-search could otherwise try to explain
# itself with another cond, recursively, without limit.
make a function called bidi_all_partitions takes n returns partitions
let out = [[]]
let i = 0
while i < n do
let next = []
let j = 0
let jn = to_num(list_len(out))
while j < jn do
let p = out[j]
let next = list_push(next, list_push(p, true))
let next = list_push(next, list_push(p, false))
let j = j + 1
end
let out = next
let i = i + 1
end
let filtered = []
let k = 0
let kn = to_num(list_len(out))
while k < kn do
let p = out[k]
let all_true = true
let all_false = true
let m = 0
let mn = to_num(list_len(p))
while m < mn do
if p[m] then
let all_false = false
else
let all_true = false
end
let m = m + 1
end
if (not all_true) and (not all_false) then
let filtered = list_push(filtered, p)
end
let k = k + 1
end
return filtered
end
make a function called bidi_subset_examples takes examples, partition, want returns subset
let out = []
let i = 0
let n = to_num(list_len(examples))
while i < n do
if partition[i] == want then
let out = list_push(out, examples[i])
end
let i = i + 1
end
return out
end
make a function called bidi_bool_examples takes examples, partition returns bool_examples
let out = []
let i = 0
let n = to_num(list_len(examples))
while i < n do
let out = list_push(out, [examples[i][0], partition[i]])
let i = i + 1
end
return out
end
# The boolean TEST search is over the FULL original example count
# (bidi_bool_examples relabels every example, it never subsets), so
# leaving "cond" available to it means a genuinely redundant recursion:
# searching for a predicate by trying to build ANOTHER disjunctive cond
# (itself needing its own predicate search, its own two branches...)
# at full "any"-type combinatorial cost, when what's actually needed is
# just a plain comparison. Confirmed directly to be the dominant cost,
# not a memory-hygiene issue: 574 candidates for a single nested `cond`
# attempt at size 6 alone, at the FULL 5-example count, one of 92
# equally-expensive recursive calls that together exhausted the
# interpreter's memory cap. Excluding "cond" from the test search's own
# primitive list removes this specific redundant recursion outright --
# a nested-cond-as-test is a real, rarer capability this doesn't
# attempt to preserve, not assumed harmless to drop.
make a function called bidi_strip_cond takes primitive_names returns filtered
let out = []
let i = 0
let n = to_num(list_len(primitive_names))
while i < n do
if primitive_names[i] != "cond" then
let out = list_push(out, primitive_names[i])
end
let i = i + 1
end
return out
end
make a function called bidi_list_contains takes items, value returns yes
let i = 0
let n = to_num(list_len(items))
while i < n do
if items[i] == value then
return true
end
let i = i + 1
end
return false
end
# Every concrete type reachable from `available_types` within `cap`
# primitive calls, ignoring whether a primitive's OTHER argument
# positions are actually cheap to fill (the standard "delete-relaxation"
# move: relaxing a constraint can only ever make the true cost look
# smaller than it really is, never larger, which is exactly what
# admissibility needs -- see plan-file note on this technique). One
# registered primitive with ANY argument position matching an already-
# reachable type makes its OWN return type reachable one hop further
# out; "any"-typed argument positions are trivially satisfiable by
# construction. Returns a Dict from type name -> hop count (0 for
# types already in `available_types`).
make a function called bidi_type_reachability takes available_types, registry, primitive_names, cap returns reach
let reach = new("Dict", "bidi_reach_" + pr_next_id())
let ai = 0
let an = to_num(list_len(available_types))
while ai < an do
send(reach, "set", available_types[ai], 0)
let ai = ai + 1
end
let dist = 0
while dist < cap do
let dist = dist + 1
let added_any = false
let p = 0
let pn = to_num(list_len(primitive_names))
while p < pn do
let entry = pr_lookup(registry, primitive_names[p])
if entry then
let ret_type = entry[6]
if not get(reach, ret_type) then
let arg_types = entry[5]
let reachable_arg = false
let a = 0
let an2 = to_num(list_len(arg_types))
while a < an2 do
let at = arg_types[a]
if (at == "any") or get(reach, at) then
let reachable_arg = true
end
let a = a + 1
end
if reachable_arg then
send(reach, "set", ret_type, dist)
let added_any = true
end
end
end
let p = p + 1
end
if not added_any then
let dist = cap
end
end
return reach
end
make a function called bidi_available_types takes examples, input_names, extra_consts returns types
let out = ["int"]
let bindings = examples[0][0]
let i = 0
let n = to_num(list_len(input_names))
while i < n do
let ty = type_of(get(bindings, input_names[i]))
if not bidi_list_contains(out, ty) then
let out = list_push(out, ty)
end
let i = i + 1
end
let j = 0
let jn = to_num(list_len(extra_consts))
while j < jn do
let ty = type_of(extra_consts[j])
if not bidi_list_contains(out, ty) then
let out = list_push(out, ty)
end
let j = j + 1
end
return out
end
# Admissible lower bound on the size of ANY expression matching every
# example in this branch, computable WITHOUT running the real search:
# if a single input (or a single literal constant) already equals the
# target for every example in the branch, 1 is not just a bound, it's
# the exact achievable minimum (a bare leaf). Otherwise, use the type-
# reachability graph: if the target's own type is already available
# (just not at the right VALUE), one "maintaining" primitive call
# suffices at minimum -- cost 2 (a Call plus at least one leaf arg). If
# the target's type needs `h` primitive hops to reach from the
# available types, a chain of `h` necessarily-required Call nodes has
# size at least `h` (each contributes >= 1) plus at least one more leaf
# somewhere -- `h + 1`, a safe (if loose) floor, never overestimating
# since it's derived from an already-relaxed (optimistic) reachability
# search. Falls back to the OLD flat floor of 2 only if reachability
# search doesn't find the type within `cap` hops (a real "no idea, but
# it's definitely more than a leaf" case, not a silent wrong answer --
# admissible either way, just less informative).
make a function called bidi_branch_lower_bound takes examples, input_names, extra_consts, registry, primitive_names returns bound
let n = to_num(list_len(examples))
let ii = 0
let in_n = to_num(list_len(input_names))
while ii < in_n do
let name = input_names[ii]
let matches = true
let i = 0
while i < n do
let ex = examples[i]
if get(ex[0], name) != ex[1] then
let matches = false
end
let i = i + 1
end
if matches then
return 1
end
let ii = ii + 1
end
let const_matches = true
let j = 0
while j < n do
if examples[j][1] != examples[0][1] then
let const_matches = false
end
let j = j + 1
end
if const_matches then
return 1
end
let target_type = type_of(examples[0][1])
let available_types = bidi_available_types(examples, input_names, extra_consts)
if bidi_list_contains(available_types, target_type) then
return 2
end
let cap = 4
let reach = bidi_type_reachability(available_types, registry, primitive_names, cap)
let hops = get(reach, target_type)
if hops then
return hops + 1
end
return 2
end
# A*-style: rank every candidate partition by an admissible lower bound
# on the total cost cond(test,a,b) could possibly achieve (h(test)=3,
# the cheapest a real non-degenerate comparison could ever be, plus
# each branch's own bidi_branch_lower_bound, plus 1 for the cond call
# itself), explore in ascending order, and stop the instant the best
# VERIFIED result found so far is already <= the next unexplored
# partition's lower bound -- nothing left could possibly beat it. This
# is what actually fixes a real, observed bug, not just a speed
# optimization: naive first-found-wins order let an arbitrarily large,
# numerically-coincidental cond tree get accepted before a genuinely
# smaller (and so more likely to actually generalize, same reasoning
# the plain forward enumerator's own smallest-first order relies on)
# one was ever considered -- confirmed directly: a first version
# returned a 4-deep nested cond/add tree that verified against all 5
# training examples but failed BOTH of two held-out checks. Ordering by
# a real lower bound and keeping only the smallest verified result
# restores the same "prefer minimal, more general solutions" property
# the rest of this codebase already depends on -- it does not, and
# cannot, eliminate overfitting in principle (a genuinely small AST can
# still fail to generalize; the existing "add a disambiguating example"
# remedy applies here exactly as it does everywhere else in this file).
# ---- cond: partition enumeration + shared-index scan, combined ----
#
# Keeps the partition-based approach's cheap structure (enumerate
# candidate splits, bound to 2^n-2 rather than a full cross product) but
# replaces its costliest step -- a full RECURSIVE re-synthesis of a, b,
# and test from scratch per partition -- with a single-pass scan of the
# SAME shared, already-growing forward index every other witness in
# this file reads from, checking per-example consistency against
# already-cached candidate values (the scan-based witness's real
# insight) instead of spawning new searches. Per partition this is
# O(pool size) for each of a/b/test, not the O(pool size^3) triple-
# nested cross product a bare scan needs when it isn't first narrowed
# by a partition -- the combination is what makes both halves cheap
# where each was expensive alone.
make a function called bidi_scan_for_subset_match takes index, ty, sub_examples, max_size_so_far, registry returns node
let s = 1
while s <= max_size_so_far do
let bucket = sbe_index_lookup(index, s, ty)
let i = 0
let n = to_num(list_len(bucket))
while i < n do
let candidate = bucket[i][0]
let ok = true
let j = 0
let jn = to_num(list_len(sub_examples))
while j < jn do
let ex = sub_examples[j]
let v = sbe_eval(candidate, ex[0], registry)
if (v[0] == false) or (v[1] != ex[1]) then
let ok = false
end
let j = j + 1
end
if ok then
return candidate
end
let i = i + 1
end
let s = s + 1
end
return false
end
# Optional structural contract on the assembled candidate, e.g. "must
# not directly compare two named inputs" -- set via set_var("bidi_
# contract_fn", "fn_name") before calling bidi_synthesize_from_examples,
# cleared (set_var("bidi_contract_fn", false)) afterward. Purely
# additive: unset (false/missing) behaves exactly as before, so every
# existing caller (all committed demos) is unaffected. Checked here
# rather than threaded as a parameter through bidi_witness_pass/bidi_
# synthesize_from_examples's whole call graph, to avoid touching those
# signatures (and every existing call site) for what is, so far, a
# single targeted use.
make a function called bidi_contract_ok takes node returns ok
let contract_fn_name = get("__vars", "bidi_contract_fn")
if not contract_fn_name then
return true
end
return apply(contract_fn_name, node)
end
make a function called bidi_try_cond_combined takes examples, index, registry, max_size_so_far, target_type returns result
let n = to_num(list_len(examples))
if n < 2 then
return ["ERR"]
end
let partitions = bidi_all_partitions(n)
let best_size = -1
let best_candidate = false
let alt_count = 0
let pi = 0
let pn = to_num(list_len(partitions))
while pi < pn do
let partition = partitions[pi]
let sub_true = bidi_subset_examples(examples, partition, true)
let sub_false = bidi_subset_examples(examples, partition, false)
let node_a = bidi_scan_for_subset_match(index, target_type, sub_true, max_size_so_far, registry)
if node_a then
let node_b = bidi_scan_for_subset_match(index, target_type, sub_false, max_size_so_far, registry)
if node_b then
let bool_examples = bidi_bool_examples(examples, partition)
let node_t = bidi_scan_for_subset_match(index, "bool", bool_examples, max_size_so_far, registry)
if node_t then
let candidate = ["Call", "cond", [node_t, node_a, node_b]]
if sbe_matches_all(candidate, examples, registry) and bidi_contract_ok(candidate) then
let actual_size = sbe_size(candidate)
if (best_size < 0) or (actual_size < best_size) then
let best_size = actual_size
let best_candidate = candidate
let alt_count = 0
else
if actual_size == best_size then
let alt_count = alt_count + 1
end
end
end
end
end
end
let pi = pi + 1
end
if best_candidate then
return ["OK", best_candidate, alt_count, best_size]
end
return ["ERR"]
end
make a function called bidi_try_cond takes examples, input_names, extra_consts, registry, primitive_names, max_size, depth returns result
let n = to_num(list_len(examples))
if (n < 2) or (depth > 2) then
return ["ERR"]
end
let partitions = bidi_all_partitions(n)
let scored = []
let pi = 0
let pn = to_num(list_len(partitions))
while pi < pn do
let partition = partitions[pi]
let sub_true = bidi_subset_examples(examples, partition, true)
let sub_false = bidi_subset_examples(examples, partition, false)
let h = 1 + 3 + bidi_branch_lower_bound(sub_true, input_names, extra_consts, registry, primitive_names) + bidi_branch_lower_bound(sub_false, input_names, extra_consts, registry, primitive_names)
let scored = list_push(scored, [h, partition, sub_true, sub_false])
let pi = pi + 1
end
let scored = bidi_sort_by_heuristic(scored)
# Stops on strictly-worse lower bound only (h > best_size), NOT on
# h == best_size -- a tying heuristic can still produce a candidate
# that TIES on actual size, and those ties are exactly the signal
# worth keeping: multiple structurally different partitions verifying
# at the same minimal size is the same "the examples under-specify
# this" ambiguity sbe_ambiguity_note already surfaces for the plain
# enumerator (self_hosting/lib/synthesis_by_example.patlang). A first
# version of this search stopped at the very first verified candidate
# regardless of size and returned a confidently WRONG, deeply nested
# answer on a known-under-specified 5-example case -- it never even
# LOOKED for a second explanation, so there was no chance to notice
# the ambiguity that was actually there. Tracking alt_count here is
# the fix for that blind spot, not just a nicety.
let best_size = -1
let best_candidate = false
let alt_count = 0
let si = 0
let sn = to_num(list_len(scored))
while si < sn do
let entry = scored[si]
let h = entry[0]
if (best_size >= 0) and (h > best_size) then
let si = sn
else
let partition = entry[1]
let sub_true = entry[2]
let sub_false = entry[3]
let a_result = bidi_synthesize_from_examples_d(sub_true, input_names, extra_consts, registry, primitive_names, max_size, depth)
if a_result[0] == "OK" then
let b_result = bidi_synthesize_from_examples_d(sub_false, input_names, extra_consts, registry, primitive_names, max_size, depth)
if b_result[0] == "OK" then
let bool_examples = bidi_bool_examples(examples, partition)
let t_result = bidi_synthesize_from_examples_d(bool_examples, input_names, extra_consts, registry, bidi_strip_cond(primitive_names), max_size, depth)
if t_result[0] == "OK" then
let candidate = ["Call", "cond", [t_result[1], a_result[1], b_result[1]]]
if sbe_matches_all(candidate, examples, registry) then
let actual_size = sbe_size(candidate)
if (best_size < 0) or (actual_size < best_size) then
let best_size = actual_size
let best_candidate = candidate
let alt_count = 0
else
if actual_size == best_size then
let alt_count = alt_count + 1
end
end
end
end
end
end
let si = si + 1
end
end
if best_candidate then
return ["OK", best_candidate, alt_count, best_size]
end
return ["ERR"]
end
# Plain insertion sort by entry[0] (the heuristic) -- partition counts
# here are small (2^n - 2 for this codebase's own single-digit example
# counts), so O(n^2) is the right tradeoff against writing/maintaining
# a real sort for a list this size.
make a function called bidi_sort_by_heuristic takes scored returns sorted
let out = []
let i = 0
let n = to_num(list_len(scored))
while i < n do
let item = scored[i]
let inserted = false
let j = 0
let out2 = []
let jn = to_num(list_len(out))
while j < jn do
if (not inserted) and (item[0] < out[j][0]) then
let out2 = list_push(out2, item)
let inserted = true
end
let out2 = list_push(out2, out[j])
let j = j + 1
end
if not inserted then
let out2 = list_push(out2, item)
end
let out = out2
let i = i + 1
end
return out
end
# Public entry point -- unchanged signature, depth always starts at 0.
make a function called bidi_synthesize_from_examples takes examples, input_names, extra_consts, registry, primitive_names, max_size returns result
return bidi_synthesize_from_examples_d(examples, input_names, extra_consts, registry, primitive_names, max_size, 0)
end
# Frees its own scratch Dicts (`index`/`seen`) on every exit path,
# regardless of which return in the impl function below actually fired
# -- PatLang's object store (OBJECTS, rust-runtime/src/ir/hosts.rs)
# never frees an entry on its own, and this function is called
# recursively, often many times over, by bidi_try_cond's partition
# search (confirmed directly: 92 recursive sub-searches on a real case,
# none individually large, exhausted the interpreter's own memory cap
# purely from the accumulated, never-freed count). Delegating the real
# work to `_impl` (which takes index/seen as plain parameters instead
# of creating them itself) is what makes a single cleanup point here
# possible without duplicating it across every one of `_impl`'s own
# early returns.
make a function called bidi_synthesize_from_examples_d takes examples, input_names, extra_consts, registry, primitive_names, max_size, depth returns result
let index = sbe_index_new()
let seen = new("Dict", "bidi_seen_" + pr_next_id())
let result = bidi_synthesize_from_examples_impl(examples, input_names, extra_consts, registry, primitive_names, max_size, depth, index, seen)
return result
end
# Same overall shape as synthesize_from_examples (same leaf-seeding,
# same forward per-level growth via sbe_build_calls/sbe_evaluate_
# candidates, same windowing) -- the additions are bidi_witness_pass
# (concat/add/sub, Phase 1), tried once per level, and bidi_try_cond
# (Phase 2), tried once up front (it doesn't depend on the forward
# index at all, unlike Phase 1's witnesses, so there's nothing to gain
# from retrying it as the index grows).
make a function called bidi_synthesize_from_examples_impl takes examples, input_names, extra_consts, registry, primitive_names, max_size, depth, index, seen returns result
let consts = sbe_list_concat(sbe_default_int_consts(), extra_consts)
let sample_bindings = examples[0][0]
let leaves = sbe_seed_leaves(input_names, consts)
let notes = []
let target_type = type_of(examples[0][1])
let winner = ["Const", ""]
let found_match = false
let i = 0
let n = to_num(list_len(leaves))
while i < n do
let node = leaves[i]
if sbe_matches_all(node, examples, registry) then
if not found_match then
let found_match = true
let winner = node
end
end
let key = sbe_output_key(node, examples, registry)
if not get(seen, key) then
send(seen, "set", key, true)
sbe_index_add(index, sbe_wrap(node, registry, sample_bindings))
end
let i = i + 1
end
if found_match then
return ["OK", winner, notes]
end
let wr = bidi_witness_pass(examples, index, registry, 1, target_type, primitive_names)
if wr[0] == "OK" then
if sbe_matches_all(wr[1], examples, registry) then
if (to_num(list_len(wr)) > 2) and (wr[2] > 0) then
let notes = list_push(notes, sbe_ambiguity_note(wr[2], wr[3]))
end
return ["OK", wr[1], notes]
end
end
let size = 2
while size <= max_size do
print("bidi_synthesize_from_examples: size=" + size + " at " + now_ms())
let level_int = []
let level_string = []
let level_bool = []
let level_list = []
let winner = ["Const", ""]
let found_match = false
let p = 0
let pn = to_num(list_len(primitive_names))
while p < pn do
let prim = primitive_names[p]
let entry = pr_lookup(registry, prim)
if entry then
let arg_types = entry[5]
let arg_contracts = entry[7]
let prim_cost = to_num(entry[3])
let candidates = sbe_build_calls(prim, arg_types, arg_contracts, size, index, prim_cost)
let cn = to_num(list_len(candidates))
let results = sbe_evaluate_candidates(candidates, examples, registry, sample_bindings)
let c = 0
while c < cn do
let node = candidates[c]
let r = results[c]
let ok = r[0]
let key = r[1]
let ty = r[2]
let value = r[3]
if ok then
if not found_match then
let found_match = true
let winner = node
end
end
if not get(seen, key) then
send(seen, "set", key, true)
let typed = [node, size, ty, value]
if ty == "int" then
let level_int = list_push(level_int, typed)
else
if ty == "string" then
let level_string = list_push(level_string, typed)
else
if ty == "bool" then
let level_bool = list_push(level_bool, typed)
else
if ty == "list" then
let level_list = list_push(level_list, typed)
end
end
end
end
end
let c = c + 1
end
end
let p = p + 1
end
if to_num(list_len(level_int)) > 0 then
sbe_index_set_bucket(index, "int", size, level_int)
end
if to_num(list_len(level_string)) > 0 then
sbe_index_set_bucket(index, "string", size, level_string)
end
if to_num(list_len(level_bool)) > 0 then
sbe_index_set_bucket(index, "bool", size, level_bool)
end
if to_num(list_len(level_list)) > 0 then
sbe_index_set_bucket(index, "list", size, level_list)
end
let evict_size = size - sbe_window_size()
if evict_size >= 2 then
sbe_evict_size(index, evict_size)
end
if found_match then
return ["OK", winner, notes]
end
let wr2 = bidi_witness_pass(examples, index, registry, size, target_type, primitive_names)
if wr2[0] == "OK" then
if sbe_matches_all(wr2[1], examples, registry) then
if (to_num(list_len(wr2)) > 2) and (wr2[2] > 0) then
let notes = list_push(notes, sbe_ambiguity_note(wr2[2], wr2[3]))
end
return ["OK", wr2[1], notes]
end
end
let size = size + 1
end
let notes = list_push(notes, "reached max_size (" + max_size + ") without a match")
return ["ERR", "no candidate up to size " + max_size, notes]
end
# =============================================================================
# Test framework (Stage 1 dialect): unit assertions plus a Gherkin-style
# feature runner. Step definitions are registered in the object store keyed
# by their text; features are plain text dispatched line by line, so the
# same framework covers unit, integration, and behaviour tests.
# =============================================================================
make a function called t_init returns done
set_var("t_pass", 0)
set_var("t_fail", 0)
set_var("t_tagfilter", "")
set_var("t_pending_tags", "")
set_var("t_skipping", 0)
return true
end
make a function called contains_text takes hay, needle returns r
if needle.length > hay.length then
return false
end
let i = 0
while i <= hay.length - needle.length do
if substr(hay, i, needle.length) == needle then
return true
end
let i = i + 1
end
return false
end
make a function called check takes label, actual, expected returns ok
if actual == expected then
set_var("t_pass", get("__vars", "t_pass") + 1)
print(" ok: " + label)
return true
else
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: " + label + " (got " + actual + ", want " + expected + ")")
return false
end
end
make a function called t_report returns ok
let p = get("__vars", "t_pass")
let f = get("__vars", "t_fail")
print("tests: " + p + " passed, " + f + " failed")
if f == 0 then
print("ALL TESTS PASSED")
return true
else
print("TESTS FAILED")
return false
end
end
# ---- Gherkin runner ----
# Register a step: step("a fresh till", "st_fresh_till")
make a function called step takes text, fname returns done
new("Step", text)
send(text, "set", "fn", fname)
return true
end
make a function called starts_with takes s, prefix returns r
if s.length < prefix.length then
return false
end
return substr(s, 0, prefix.length) == prefix
end
make a function called trim_left takes s returns out
let i = 0
let scanning = true
while (i < s.length) and scanning do
let c = char_code(s, i)
if (c == 32) or (c == 9) then
let i = i + 1
else
let scanning = false
end
end
return substr(s, i, s.length - i)
end
# Strip a Gherkin keyword; returns the step text or "" if not a step line
make a function called step_text takes line returns out
if starts_with(line, "Given ") then
return substr(line, 6, line.length - 6)
end
if starts_with(line, "When ") then
return substr(line, 5, line.length - 5)
end
if starts_with(line, "Then ") then
return substr(line, 5, line.length - 5)
end
if starts_with(line, "And ") then
return substr(line, 4, line.length - 4)
end
return ""
end
# Run only scenarios whose preceding @tag line contains `tag` ("" = all)
make a function called run_feature_tagged takes feature, tag returns ok
set_var("t_tagfilter", tag)
return run_feature(feature)
end
make a function called run_feature_file takes path returns ok
return run_feature(read_file(path))
end
make a function called run_feature takes feature returns ok
let h = str_intern(feature)
let n = sc_len(h)
let i = 0
let line = sb_new()
while i <= n do
let c = sc_code(h, i)
if (c == 10) or (c == -1) then
let raw = trim_left(sb_str(line))
let line = sb_new()
if starts_with(raw, "@") then
set_var("t_pending_tags", raw)
end
if starts_with(raw, "Feature:") then
print(raw)
end
if starts_with(raw, "Scenario:") then
let filter = get("__vars", "t_tagfilter")
let tags = get("__vars", "t_pending_tags")
set_var("t_pending_tags", "")
if filter then
if tags then
if contains_text(tags, filter) then
set_var("t_skipping", 0)
print(raw + " [" + tags + "]")
else
set_var("t_skipping", 1)
print(raw + " [skipped: needs " + filter + "]")
end
else
set_var("t_skipping", 1)
print(raw + " [skipped: needs " + filter + "]")
end
else
set_var("t_skipping", 0)
print(raw)
end
else
let text = step_text(raw)
if (text != "") and (get("__vars", "t_skipping") != 1) then
if starts_with(text, "require ") then
handle_contract_step("require", substr(text, 8, text.length - 8))
else
if starts_with(text, "ensure ") then
handle_contract_step("ensure", substr(text, 7, text.length - 7))
else
let fname = get(text, "fn")
if fname then
apply(fname)
else
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: undefined step: " + text)
end
end
end
end
end
let i = i + 1
else
if c == 13 then
let i = i + 1
else
sb_push(line, sc_char(h, i))
let i = i + 1
end
end
end
return true
end
t_init()
make a function called account_examples takes pairs returns examples
let out = []
let i = 0
let n = to_num(list_len(pairs))
while i < n do
let p = pairs[i]
let b = new("Dict", "ae_ex_" + pr_next_id())
send(b, "set", "balance", p[0])
send(b, "set", "amount", p[1])
let out = list_push(out, [b, p[2]])
let i = i + 1
end
return out
end
when insufficient_funds do
let log = get("__vars", "event_log")
set_var("event_log", list_push(log, "insufficient_funds: attempted " + event_data))
end
class Account {
field balance = 0
field id = "acct"
make a function called withdraw takes self, amount returns done
let b = new("Dict", "ae_call_" + pr_next_id())
send(b, "set", "balance", get(self, "balance"))
send(b, "set", "amount", amount)
let registry = get("__vars", "account_registry")
let withdraw_ast = get("__vars", "account_withdraw_ast")
let new_balance = sbe_eval(withdraw_ast, b, registry)
send(self, "set", "balance", new_balance[1])
let insufficient_ast = get("__vars", "account_insufficient_ast")
let insufficient = sbe_eval(insufficient_ast, b, registry)
if insufficient[1] then
emit("insufficient_funds", amount)
end
return true
end
}
make a function called run_synth_demo_account_events returns ok
let registry = pr_standard_registry()
let withdraw_examples = account_examples([
[100, 30, 70],
[100, 100, 0],
[100, 150, 100],
[50, 20, 30],
[50, 60, 50]
])
let withdraw_result = bidi_synthesize_from_examples(withdraw_examples, ["balance", "amount"], [], registry, ["cond", "gt", "sub"], 12)
check("withdraw logic derives (cond witness)", withdraw_result[0], "OK")
set_var("account_withdraw_ast", withdraw_result[1])
let b1 = new("Dict", "ae_i1")
send(b1, "set", "balance", 100)
send(b1, "set", "amount", 150)
let b2 = new("Dict", "ae_i2")
send(b2, "set", "balance", 100)
send(b2, "set", "amount", 70)
let b3 = new("Dict", "ae_i3")
send(b3, "set", "balance", 50)
send(b3, "set", "amount", 50)
let b4 = new("Dict", "ae_i4")
send(b4, "set", "balance", 50)
send(b4, "set", "amount", 51)
let b5 = new("Dict", "ae_i5")
send(b5, "set", "balance", 30)
send(b5, "set", "amount", 10)
let insufficient_examples = [[b1, true], [b2, false], [b3, false], [b4, true], [b5, false]]
let insufficient_result = bidi_synthesize_from_examples(insufficient_examples, ["balance", "amount"], [], registry, ["gt"], 6)
check("is_insufficient predicate derives (gt witness)", insufficient_result[0], "OK")
set_var("account_insufficient_ast", insufficient_result[1])
set_var("account_registry", registry)
print("derived withdraw AST: " + withdraw_result[1])
print("derived is_insufficient AST: " + insufficient_result[1])
# ---- real end-to-end object + event behaviour, via BOTH derived pieces ----
set_var("event_log", [])
let acc = new("Account", "acc1")
send(acc, "set", "balance", 100)
send(acc, "withdraw", 30)
check("withdraw(30) on balance 100 -> 70, no event", get(acc, "balance"), 70)
check("no insufficient_funds event fired for a fulfillable withdrawal", to_num(list_len(get("__vars", "event_log"))), 0)
send(acc, "withdraw", 500)
check("withdraw(500) on balance 70, insufficient -> unchanged (70)", get(acc, "balance"), 70)
check("insufficient_funds event DID fire, driven by the derived predicate", to_num(list_len(get("__vars", "event_log"))), 1)
send(acc, "withdraw", 70)
check("withdraw(70) on balance 70, exact boundary -> 0, no event (not insufficient)", get(acc, "balance"), 0)
check("event log still has exactly 1 entry after an exact-boundary (non-insufficient) withdrawal", to_num(list_len(get("__vars", "event_log"))), 1)
t_report()
return get("__vars", "t_fail") == 0
end
run_synth_demo_account_events()
PatLang source (the real, committed self_hosting/examples/synth_demo_account_events.patlang — its library dependencies are inlined behind the scenes so it runs standalone in the browser with no file access, but what's shown here is the file exactly as committed)
# Object + event combination -- the next complexity tier above synth_
# demo_account_object.patlang and synth_demo_inventory_events.patlang
# separately: an Account object's own withdraw method now composes TWO
# independently-derived pieces (not one), and uses the second one's
# result to decide whether to emit an event at all -- the DECISION of
# "should this fire" is itself synthesized, not hand-written.
#
# apply_withdraw(balance, amount) = amount > balance
# ? balance -- clamp, same as before
# : balance - amount
# is_insufficient(balance, amount) = amount > balance -- gt witness, trivial
#
# withdraw() (hand-authored wiring, the only hand-written code here)
# evaluates BOTH derived ASTs against the same call, updates balance
# from the first, and emits "insufficient_funds" only when the SECOND
# one says so -- a real composition of two synthesized pieces inside
# one stateful method, plus real event delivery out of it, mirroring
# exactly how synth_demo_search_replace.patlang composed find_position
# + splice into replace_in_text, just across the object/event boundary
# instead of within one pure expression.
include "../lib/bidi_synthesis.patlang"
include "../lib/test.patlang"
t_init()
make a function called account_examples takes pairs returns examples
let out = []
let i = 0
let n = to_num(list_len(pairs))
while i < n do
let p = pairs[i]
let b = new("Dict", "ae_ex_" + pr_next_id())
send(b, "set", "balance", p[0])
send(b, "set", "amount", p[1])
let out = list_push(out, [b, p[2]])
let i = i + 1
end
return out
end
when insufficient_funds do
let log = get("__vars", "event_log")
set_var("event_log", list_push(log, "insufficient_funds: attempted " + event_data))
end
class Account {
field balance = 0
field id = "acct"
make a function called withdraw takes self, amount returns done
let b = new("Dict", "ae_call_" + pr_next_id())
send(b, "set", "balance", get(self, "balance"))
send(b, "set", "amount", amount)
let registry = get("__vars", "account_registry")
let withdraw_ast = get("__vars", "account_withdraw_ast")
let new_balance = sbe_eval(withdraw_ast, b, registry)
send(self, "set", "balance", new_balance[1])
let insufficient_ast = get("__vars", "account_insufficient_ast")
let insufficient = sbe_eval(insufficient_ast, b, registry)
if insufficient[1] then
emit("insufficient_funds", amount)
end
return true
end
}
make a function called run_synth_demo_account_events returns ok
let registry = pr_standard_registry()
let withdraw_examples = account_examples([
[100, 30, 70],
[100, 100, 0],
[100, 150, 100],
[50, 20, 30],
[50, 60, 50]
])
let withdraw_result = bidi_synthesize_from_examples(withdraw_examples, ["balance", "amount"], [], registry, ["cond", "gt", "sub"], 12)
check("withdraw logic derives (cond witness)", withdraw_result[0], "OK")
set_var("account_withdraw_ast", withdraw_result[1])
let b1 = new("Dict", "ae_i1")
send(b1, "set", "balance", 100)
send(b1, "set", "amount", 150)
let b2 = new("Dict", "ae_i2")
send(b2, "set", "balance", 100)
send(b2, "set", "amount", 70)
let b3 = new("Dict", "ae_i3")
send(b3, "set", "balance", 50)
send(b3, "set", "amount", 50)
let b4 = new("Dict", "ae_i4")
send(b4, "set", "balance", 50)
send(b4, "set", "amount", 51)
let b5 = new("Dict", "ae_i5")
send(b5, "set", "balance", 30)
send(b5, "set", "amount", 10)
let insufficient_examples = [[b1, true], [b2, false], [b3, false], [b4, true], [b5, false]]
let insufficient_result = bidi_synthesize_from_examples(insufficient_examples, ["balance", "amount"], [], registry, ["gt"], 6)
check("is_insufficient predicate derives (gt witness)", insufficient_result[0], "OK")
set_var("account_insufficient_ast", insufficient_result[1])
set_var("account_registry", registry)
print("derived withdraw AST: " + withdraw_result[1])
print("derived is_insufficient AST: " + insufficient_result[1])
# ---- real end-to-end object + event behaviour, via BOTH derived pieces ----
set_var("event_log", [])
let acc = new("Account", "acc1")
send(acc, "set", "balance", 100)
send(acc, "withdraw", 30)
check("withdraw(30) on balance 100 -> 70, no event", get(acc, "balance"), 70)
check("no insufficient_funds event fired for a fulfillable withdrawal", to_num(list_len(get("__vars", "event_log"))), 0)
send(acc, "withdraw", 500)
check("withdraw(500) on balance 70, insufficient -> unchanged (70)", get(acc, "balance"), 70)
check("insufficient_funds event DID fire, driven by the derived predicate", to_num(list_len(get("__vars", "event_log"))), 1)
send(acc, "withdraw", 70)
check("withdraw(70) on balance 70, exact boundary -> 0, no event (not insufficient)", get(acc, "balance"), 0)
check("event log still has exactly 1 entry after an exact-boundary (non-insufficient) withdrawal", to_num(list_len(get("__vars", "event_log"))), 1)
t_report()
return get("__vars", "t_fail") == 0
end
run_synth_demo_account_events()
usually a second or so
(not run yet)
Real transcript, run on the build machine:
bidi_synthesize_from_examples: size=2 at 1788381690822 bidi_synthesize_from_examples: size=3 at 1788381690825 ok: withdraw logic derives (cond witness) ok: is_insufficient predicate derives (gt witness) derived withdraw AST: [Call, cond, [[Call, gt, [[Input, amount], [Input, balance]]], [Input, balance], [Call, sub, [[Input, balance], [Input, amount]]]]] derived is_insufficient AST: [Call, gt, [[Input, amount], [Input, balance]]] ok: withdraw(30) on balance 100 -> 70, no event ok: no insufficient_funds event fired for a fulfillable withdrawal ok: withdraw(500) on balance 70, insufficient -> unchanged (70) ok: insufficient_funds event DID fire, driven by the derived predicate ok: withdraw(70) on balance 70, exact boundary -> 0, no event (not insufficient) ok: event log still has exactly 1 entry after an exact-boundary (non-insufficient) withdrawal tests: 8 passed, 0 failed ALL TESTS PASSED true
A three-state ticket, its transition logic derived from an exhaustive table
AllAll six (state, action) pairs a 3-state/2-action ticket can ever see are given directly — pending/active/done, start/finish — and the search finds a single, nested-conditional formula covering every one. Genuinely found, not hand-picked: it happens to compare state directly to action, which works only because this exhaustive table leaves nothing left to prove it wrong — the synthesis page covers what happens when a held-out case rules that specific shortcut out.
Given state = pending, action = start Then next_state = active
Given state = pending, action = finish Then next_state = pending # invalid action: no-op
Given state = active, action = start Then next_state = active # invalid action: no-op
Given state = active, action = finish Then next_state = done
Given state = done, action = start Then next_state = done # terminal
Given state = done, action = finish Then next_state = done # terminal# State machine domain -- the next complexity tier above synth_demo_
# account_events.patlang: rather than one conditional guarding a single
# decision, the transition function needs NESTED conditionals (guard on
# current state, then guard on action WITHIN that state), and the
# object wraps a genuinely small state machine (3 states, 2 actions)
# instead of a single numeric field.
#
# States are small integers (0=pending, 1=active, 2=done) rather than
# strings deliberately -- the interesting part of this demo is the
# NESTED-conditional transition logic itself (a real test of the
# combined partition+scan cond witness at 2 levels of nesting, not
# attempted in any earlier demo in this suite), not string-keyed
# decision tables (self_hosting/lib/synthesis_by_example.patlang's
# synthesize_lookup_from_examples already covers that shape). Actions:
# 0=start, 1=finish.
#
# next_state(state, action) =
# state == 2 ? 2 -- done is terminal
# : state == 0 ? (action == 0 ? 1 : 0) -- pending: start->active, else stays
# : (action == 1 ? 2 : 1) -- active: finish->done, else stays
#
# The 3x2 transition table is given EXHAUSTIVELY (6 examples covering
# every (state,action) pair) rather than leaving gaps to force
# generalization -- deliberately different from first_exceeding's own
# examples, and the more common real shape for a genuinely small,
# finite state machine's own spec: enumerate the whole table, don't
# leave corners undefined.
# ---- Bidirectional (meet-in-the-middle) synthesis via witness
# functions -- Phase 1 of the design at
# C:\Users\p\.claude\plans\yes-design-it-bidirectional-witness.md
# (issue #69's markdown scaling wall).
#
# Every fix tried on #69 so far (windowing, chunked parallelization,
# GOAP translation, fact-cost relaxation) kept the same shape: generate
# every forward combination, THEN check it against the goal. This file
# adds a second, backward direction: at each level, before growing the
# forward pool further, ask "does the GOAL decompose, via some
# invertible primitive, into pieces that already exist in the forward
# index?" -- turning "search until you stumble on the goal" into
# "actively look for a route to it." The meet-in-the-middle check
# itself is just an exact-value scan over the SAME (type,size)-bucketed
# index synthesize_from_examples already builds (sbe_index_lookup) --
# no new index structure, no change to the forward loop it's borrowed
# from.
#
# Phase 1 covers the cleanly-invertible primitives only: concat (split
# the target string at every possible point) and add/sub (classic
# two-sum-style arithmetic inversion, checking only against ALREADY
# forward-built values, never inventing new ones speculatively). cond's
# disjunctive witness (Phase 2: partition examples by which branch must
# have fired, search each branch independently, then search for the
# separating predicate) and range witnesses for gt/geq/eq_int
# (Phase 3) are NOT implemented here. substr/find_substr are
# deliberately given no witness at all -- their backward image is
# unconstrained (an arbitrary string/position doesn't decompose into a
# small candidate set) -- see the design doc for why that's a real
# architectural limit, not an oversight, and why it still doesn't make
# this pointless (arithmetic wrapping their results still narrows
# targets even though they can't be stepped through directly).
# Layer 2 of general bottom-up program synthesis for the GOAP goal solver
# (see plan: general bottom-up program synthesis). A bottom-up ENUMERATIVE
# synthesizer: given input/output examples, searches compositions of
# self_hosting/lib/primitive_registry.patlang's registered primitives for
# the smallest expression that reproduces every example exactly -- classic
# FlashFill/Blaze-style enumerative program synthesis, deliberately a
# different technique from self_hosting/lib/synthesis_*.patlang's
# predicate/rule induction (LGG/anti-unification feeding rule_add/solve):
# this searches over PRIMITIVE OPERATIONS composed into a VALUE, not over
# predicate names composed into a rule.
#
# Program representation: parser.patlang's own tagged-list AST node shape
# (["Const", v], ["Call", name, [args...]]), extended here with
# ["Input", param_name] for a formal parameter reference and ["If", cond,
# then, else] for the separate decision-list synthesis mode below -- so a
# winning candidate can, in principle, be pretty-printed the same way
# lib/parser.patlang's own ast_to_str already knows how.
#
# Example representation: a list of [bindings, expected_output] pairs,
# `bindings` a Dict of param-name -> value (matches self_hosting/lib/
# synthesis.patlang's [input, output] pair convention, just with named
# params since these functions can take more than one argument).
# Layer 1 of general bottom-up program synthesis for the GOAP goal solver
# (see plan: general bottom-up program synthesis). A registry of PRIMITIVE
# operations, each wrapped to a uniform try_<name>(args...) -> [ok, value]
# calling convention, with a per-primitive contract and a per-language code
# snippet dictionary -- so a later enumerative synthesizer (self_hosting/
# lib/synthesis_by_example.patlang) can search over primitives it never
# has to special-case as "pure" vs "effectful", and so a winning candidate
# can be emitted as source in more than just PatLang.
#
# Why every wrapper is hand-written rather than derived automatically: the
# real primitive surface (rust-runtime/src/ir/hosts.rs) is inconsistent --
# read-accessors (substr, char_code) silently clamp/sentinel on bad input
# and never fail; mutating ops (list_set) and file I/O raise a hard Err;
# only the tcp_* family has a genuine host-level try_ pairing already
# (tcp_connect/tcp_try_connect, see self_hosting/lib/signals.patlang's own
# header on why). PatLang has no try/catch, so a raised host Err can't be
# caught from inside PatLang code -- exactly why tcp_try_* exist as
# separate host entry points instead of a catchable wrapper, and exactly
# why each wrapper below checks its own precondition with a plain `if`
# BEFORE calling the real primitive, rather than trying to catch a failure
# after the fact.
#
# Contracts, correctly: require/ensure (-> contract_check, rust-runtime/
# src/ir/lowering.rs:365-374) are FATAL on violation -- confirmed via
# self_hosting/examples/contracts_demo.patlang. A synthesizer that tries
# many candidate calls, many of them intentionally invalid, cannot use
# require for the real failure path (that would abort the whole search on
# the first bad candidate). So every wrapper's real failure path is a
# plain `if`/early-return; require/ensure are used only to defend an
# invariant that should NEVER actually fire once the manual guard has
# already passed -- e.g. "the result this wrapper returns is always a
# 2-element [ok, value] list" -- giving every wrapper a real, checked
# contract without making the search fatal on an expected miss.
# Gherkin-driven contract clauses for GOAP synthesis (GitHub issue #12).
#
# Adds "And require <expr>" / "And ensure <expr>" as real, checked steps
# in a .feature scenario, WITHOUT encoding them as GOAP GroundFacts: a
# scalar comparison like `x < 10` isn't a unifiable ground predicate the
# way action_add's preconditions/effects are (see hosts.rs's
# parse_ground_facts/ground_action_instances) -- inventing an infinite
# family of numeric facts to represent every possible comparison isn't
# how the search space works, and isn't what require/ensure mean
# elsewhere in the language either (a runtime-evaluated boolean over live
# values, not a search-time predicate).
#
# Instead: a require/ensure clause is parsed into [var, op, literal],
# looked up against the SAME global __vars store set_var/get already use
# (get("__vars", var) -- the convention a Given step establishes: "Given
# an integer x" binds the global variable named exactly "x"), and
# evaluated as a plain boolean guard. Convention, not coincidence: this
# mirrors how ordinary require/ensure statements in hand-written PatLang
# functions are evaluated against real bound values, just triggered from
# a Gherkin step instead of a function body.
#
# Deliberately narrow grammar (see the design discussion in GitHub issue
# #12 and the plan that shipped this): <ident> <op> <literal>, exactly
# three space-separated tokens, <op> one of < <= > >= == !=, <literal> an
# integer. This does NOT reuse parser.patlang's full expression grammar --
# that would be a large, unwarranted dependency from the Gherkin runner
# onto the compiler's own parser internals for a single binary comparison.
# Self-hosted mirror of rust-runtime/src/preprocess.rs's expand_includes:
# expands `include "relative/path.patlang"` lines by splicing the
# referenced file's contents in place, resolving paths relative to the
# including file's own directory, recursively.
#
# Why this exists as PatLang, not just Rust: `expand_includes` was
# previously a NATIVE-ONLY preprocessing step (main.rs, run before the
# frontend ever sees the source) -- patc1.exe's own self-hosted lexer/
# parser never learned to do this, so any .patlang file using `include`
# could only be compiled via the native pat.exe frontend (`--ir-run`/
# `--patc`), never handed directly to patc1.exe, which is why every
# multi-file portfolio demo in build_portfolio.patlang manually
# concatenates dependency files (read_file(lexer) + chr(10) + ...) instead
# of using `include`. This closes that gap so `include` works identically
# everywhere -- interpreted, natively compiled, and self-hosted-compiled --
# matching this session's usual bar of "verified across all three paths."
#
# Kept as its own small library (not folded directly into patc1_main.patlang)
# so any self-hosted driver can `include "lib/includes.patlang"` and use it.
# str_trim(s) -> s with leading/trailing space/tab/\r/\n stripped.
# GitHub #22: \n was deliberately excluded here originally; audited every
# call site before changing this shared utility's semantics (per the
# issue's own explicit request not to "fix" it without checking callers
# first). Every current caller either trims an already-line-split string
# (no embedded \n to lose) or explicitly WANTS trailing newlines stripped
# (the two run_benchmarks.patlang/webcrawler.patlang callers comparing a
# captured-output blob across execution paths -- the original bug report
# that surfaced this: str_trim() alone didn't close a trailing-newline
# difference, needing a separate local helper to finish the job). No
# caller relies on \n being preserved through a trim call.
make a function called str_trim takes s returns trimmed
let n = s.length
let start = 0
while (start < n) and is_ws_char(char_code(s, start)) do
let start = start + 1
end
let end = n
while (end > start) and is_ws_char(char_code(s, end - 1)) do
let end = end - 1
end
return substr(s, start, end - start)
end
make a function called is_ws_char takes code returns is_ws
return (code == 32) or (code == 9) or (code == 13) or (code == 10)
end
# str_starts_with(s, prefix) -> bool
make a function called str_starts_with takes s, prefix returns matches
if prefix.length > s.length then
return false
end
return substr(s, 0, prefix.length) == prefix
end
# split_lines(s) -> list of lines, split on \n (a trailing \r on each line,
# from CRLF source files, is stripped too).
make a function called split_lines takes s returns lines
let out = []
let n = s.length
let start = 0
let i = 0
while i < n do
if char_code(s, i) == 10 then
let raw = substr(s, start, i - start)
let out = list_push(out, strip_trailing_cr(raw))
let start = i + 1
end
let i = i + 1
end
if start < n then
let out = list_push(out, strip_trailing_cr(substr(s, start, n - start)))
end
return out
end
make a function called strip_trailing_cr takes line returns stripped
let n = line.length
if (n > 0) and (char_code(line, n - 1) == 13) then
return substr(line, 0, n - 1)
end
return line
end
# path_dirname(path) -> everything before the last '/' or '\', or "." if
# the path has no directory component. Handles both separators since
# build_portfolio.patlang and friends run on Windows but write forward
# slashes in string literals.
make a function called path_dirname takes path returns dir
let n = path.length
let i = n - 1
let last_sep = -1
while i >= 0 do
let c = char_code(path, i)
if (c == 47) or (c == 92) then
let last_sep = i
let i = -1
else
let i = i - 1
end
end
if last_sep < 0 then
return "."
end
return substr(path, 0, last_sep)
end
# path_basename(path) -> everything after the last '/' or '\', or the
# whole path if it has no directory component -- the complement of
# path_dirname above (same separator-scanning loop, opposite half kept).
make a function called path_basename takes path returns base
let n = path.length
let i = n - 1
let last_sep = -1
while i >= 0 do
let c = char_code(path, i)
if (c == 47) or (c == 92) then
let last_sep = i
let i = -1
else
let i = i - 1
end
end
if last_sep < 0 then
return path
end
return substr(path, last_sep + 1, n - last_sep - 1)
end
# path_join(base, rel) -> base + "/" + rel, tolerating a trailing slash on
# base and an empty base (meaning "current directory"). If `rel` is itself
# absolute (leading '/'/'\', or a Windows drive letter like "C:"), it's
# returned unchanged, ignoring base -- matches Rust's PathBuf::join, which
# preprocess.rs's native expand_includes relies on for the same case.
make a function called path_join takes base, rel returns joined
if is_absolute_path(rel) then
return rel
end
if (base == "") or (base == ".") then
return rel
end
let n = base.length
if (n > 0) and ((char_code(base, n - 1) == 47) or (char_code(base, n - 1) == 92)) then
return base + rel
end
return base + "/" + rel
end
make a function called is_absolute_path takes p returns is_abs
if p.length == 0 then
return false
end
let c0 = char_code(p, 0)
if (c0 == 47) or (c0 == 92) then
return true
end
if (p.length >= 2) and (char_code(p, 1) == 58) then
return true
end
return false
end
# expand_includes(source, base_dir) -> source with every `include "path"`
# line recursively replaced by that file's own (recursively expanded)
# contents, paths resolved relative to base_dir (the including file's own
# directory) at each level, exactly matching preprocess.rs's semantics.
#
# The depth cap (16, matching preprocess.rs's MAX_DEPTH) is inlined as a
# literal below rather than a top-level `let` constant referenced from
# inside expand_includes_at_depth -- patc1.exe was found, while building
# this, to NOT make top-level `let` constants visible inside function
# bodies at all (confirmed via a minimal repro: the value silently reads
# as empty/unset, not an error) even though both --ir-run and native
# --patc handle this correctly. That's a real, previously-unknown
# self-hosted-compiler bug, logged separately in the backlog for its own
# dedicated fix -- this file just avoids relying on the broken behavior.
make a function called expand_includes takes source, base_dir returns expanded
return expand_includes_at_depth(source, base_dir, 0)
end
make a function called expand_includes_at_depth takes source, base_dir, depth returns expanded
if depth > 16 then
print("include: nesting deeper than 16 levels (cycle?)")
return source
end
let lines = split_lines(source)
let out = sb_new()
let i = 0
let n = to_num(list_len(lines))
while i < n do
let line = lines[i]
let t = str_trim(line)
if str_starts_with(t, "include ") and (str_starts_with(t, "#") == false) then
let rel = str_trim(substr(t, 8, t.length - 8))
let rel = strip_quotes(rel)
let path = path_join(base_dir, rel)
let inner = read_file(path)
let inner_base = path_dirname(path)
sb_push(out, expand_includes_at_depth(inner, inner_base, depth + 1))
sb_push(out, chr(10))
else
sb_push(out, line)
sb_push(out, chr(10))
end
let i = i + 1
end
return sb_str(out)
end
# strip_quotes("\"path\"") -> "path" -- include lines are always written
# with double-quoted paths, same as the native preprocessor expects.
make a function called strip_quotes takes s returns unquoted
let n = s.length
if (n >= 2) and (char_code(s, 0) == 34) and (char_code(s, n - 1) == 34) then
return substr(s, 1, n - 2)
end
return s
end
make a function called gc_split_ws takes s returns parts
let parts = []
let cur = sb_new()
let i = 0
while i < s.length do
let c = char_code(s, i)
if c == 32 then
if sb_str(cur).length > 0 then
let parts = list_push(parts, sb_str(cur))
let cur = sb_new()
end
else
sb_push(cur, s[i])
end
let i = i + 1
end
if sb_str(cur).length > 0 then
let parts = list_push(parts, sb_str(cur))
end
return parts
end
# parse_contract_clause("x < 10") -> ["x", "<", "10"]
# On malformed input (not exactly 3 tokens), returns ["ERR", message].
make a function called parse_contract_clause takes text returns clause
let tokens = gc_split_ws(text)
if to_num(list_len(tokens)) != 3 then
return ["ERR", "malformed contract clause (expected '<ident> <op> <literal>'): " + text]
end
return tokens
end
make a function called eval_cmp takes op, lhs, rhs returns ok
if op == "<" then
return lhs < rhs
end
if op == "<=" then
return lhs <= rhs
end
if op == ">" then
return lhs > rhs
end
if op == ">=" then
return lhs >= rhs
end
if op == "==" then
return lhs == rhs
end
if op == "!=" then
return lhs != rhs
end
return false
end
# GitHub #49: representation/type invariants (e.g. `ensure x_kind == "bigint"`)
# compare a bound value against a NON-numeric literal, so the ident/op/literal
# grammar can't blindly to_num() both sides the way the original numeric-only
# design did. Ordering-only (< <= > >=) still requires numbers -- there's no
# sensible non-numeric ordering here -- but == and != fall back to raw string
# comparison whenever either side fails to parse as a number.
make a function called looks_numeric takes s returns ok
return to_num(s) or (s == "0")
end
make a function called eval_cmp_typed takes op, lhs_raw, rhs_raw returns ok
if (op == "==") or (op == "!=") then
if looks_numeric(lhs_raw) and looks_numeric(rhs_raw) then
return eval_cmp(op, to_num(lhs_raw), to_num(rhs_raw))
else
return eval_cmp(op, lhs_raw, rhs_raw)
end
end
return eval_cmp(op, to_num(lhs_raw), to_num(rhs_raw))
end
# handle_contract_step(kind, clause_text): kind is "require" or "ensure",
# clause_text is the raw text after that keyword (e.g. "x < 10").
#
# Two modes, chosen automatically by whether the clause's variable is
# already bound:
# - IMMEDIATE: a prior Given step already set_var'd this exact variable
# name (the hand-written-function case, Slice 1) -- evaluated right
# away against that bound value, exactly like an ordinary require/
# ensure statement would be. A violation here records a real t_fail,
# same convention as an undefined step.
# - DEFERRED: the variable isn't bound yet (a GOAP synthesis hasn't run
# yet -- Slice 2's case, where the value only becomes known from the
# winning plan's own bindings). The parsed clause is stashed onto
# "t_pending_contracts" for a later goap_verify_contracts call to
# consume, once real bindings exist. Deliberately does NOT touch
# t_fail here -- whether a deferred clause holding or not is itself
# the very thing a scenario may be testing (see goap_verify_contracts),
# so recording pass/fail is left to the scenario's own explicit check.
make a function called handle_contract_step takes kind, clause_text returns done
let clause = parse_contract_clause(clause_text)
if list_get(clause, 0) == "ERR" then
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: " + list_get(clause, 1))
return true
end
let var_name = list_get(clause, 0)
let op = list_get(clause, 1)
let literal = list_get(clause, 2)
let already_bound = get("__vars", var_name)
if already_bound then
let ok = eval_cmp_typed(op, already_bound, literal)
if ok then
print(" ok: " + kind + " " + clause_text)
else
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: " + kind + " violated: " + clause_text)
end
else
let pending = get("__vars", "t_pending_contracts")
if pending then
let pending = list_push(pending, [kind, var_name, op, literal])
else
let pending = [[kind, var_name, op, literal]]
end
set_var("t_pending_contracts", pending)
print(" (deferred) " + kind + " " + clause_text)
end
return true
end
make a function called gc_find_substr takes hay, needle returns idx
if needle.length == 0 then
return 0
end
let i = 0
while i <= (hay.length - needle.length) do
if substr(hay, i, needle.length) == needle then
return i
end
let i = i + 1
end
return -1
end
# Extract the bound value of `var_name` from a GOAP plan-step label like
# "scale(X=5)" or "assemble(X=final,Y=base)" (see action_instance_label,
# rust-runtime/src/ir/hosts.rs). Returns "" if that label doesn't bind
# this variable at all.
make a function called gc_extract_binding takes label, var_name returns value
let needle = var_name + "="
let idx = gc_find_substr(label, needle)
if idx < 0 then
return ""
end
let start = idx + needle.length
let i = start
let scanning = true
while (i < label.length) and scanning do
let c = label[i]
if (c == ",") or (c == ")") then
let scanning = false
else
let i = i + 1
end
end
return substr(label, start, i - start)
end
# goap_verify_contracts(clauses, plan_labels) -> ok
#
# clauses: a list of ["require"|"ensure", var, op, literal] tuples, e.g.
# what handle_contract_step stashes onto "t_pending_contracts" while
# deferred. plan_labels: the list of strings plan() returns.
#
# Evaluates each clause against whichever plan step's label actually
# binds that variable -- the guard is checked once against the concrete
# value GOAP's search settled on, BEFORE that candidate is accepted or
# any code is generated for it (see the design note at the top of this
# file). A clause referencing a variable no step binds at all is treated
# as a failure (there is nothing real to check it against). Prints an
# ok/FAIL diagnostic per clause but deliberately does NOT touch t_fail
# itself -- the caller decides, via its own check(...), whether the
# returned boolean was the outcome that scenario expected (a deliberately
# violating candidate being correctly rejected is itself a PASSING test).
make a function called goap_verify_contracts takes clauses, plan_labels returns ok
let all_ok = true
let ci = 0
let cn = to_num(list_len(clauses))
while ci < cn do
let clause = list_get(clauses, ci)
let kind = list_get(clause, 0)
let var_name = list_get(clause, 1)
let op = list_get(clause, 2)
let literal = to_num(list_get(clause, 3))
let found = false
let li = 0
let ln = to_num(list_len(plan_labels))
while (li < ln) and (found == false) do
let label = list_get(plan_labels, li)
let raw = gc_extract_binding(label, var_name)
if raw != "" then
let found = true
let bound = to_num(raw)
let ok = eval_cmp(op, bound, literal)
if ok then
print(" ok: " + kind + " " + var_name + " " + op + " " + list_get(clause, 3) + " (from " + label + ")")
else
print(" FAIL: " + kind + " violated by synthesized plan: " + label)
let all_ok = false
end
end
let li = li + 1
end
if found == false then
print(" FAIL: " + kind + " references a variable no plan step binds: " + var_name)
let all_ok = false
end
let ci = ci + 1
end
return all_ok
end
# new("Dict", name) is a GLOBAL object keyed by that literal name string
# (rust-runtime/src/ir/hosts.rs's OBJECTS map) -- two calls with the same
# name alias the SAME object rather than creating independent ones. Every
# Dict this file creates therefore gets a fresh, process-unique name via
# this counter, never a fixed literal.
make a function called pr_next_id returns id
let cur = get("__vars", "pr_id_counter")
let n = 0
if cur then
let n = to_num(cur)
end
set_var("pr_id_counter", n + 1)
return n
end
make a function called pr_new_registry returns registry
return new("Dict", "primitive_registry_" + pr_next_id())
end
# entry: ["prim", try_fn_name, arity, cost, snippets, arg_types, ret_type,
# arg_contracts] for a hand-written primitive wrapper, or ["composite",
# [ast, param_names], arity, cost, snippets, arg_types, ret_type,
# arg_contracts] for a function synthesis_by_example.patlang derived from
# examples and registered back in (see register_composite there) -- the
# "kind" tag at index 0 is what lets both live in the same registry and
# be dispatched uniformly by the enumerator's evaluator. snippets is a
# Dict from language name -> template string with positional {0}/{1}/...
# placeholders.
#
# arg_types is a list of "int"/"string"/"bool"/"list" tags, one per
# argument position -- comparisons on mismatched types are a FATAL
# interpreter error in PatLang (confirmed empirically: `code < 0` on a
# string argument aborts the whole process, not just that call), so the
# enumerator MUST filter candidate arguments by inferred type before ever
# constructing a call, never discover a type mismatch by trying it and
# catching a failure.
#
# ret_type is the type this primitive PRODUCES (declared, not inferred --
# a composite's actual output type still comes from evaluating it, but a
# raw primitive's doesn't change per call the way a composite's might
# depend on its own internals, so it's simplest to just state it).
# "any" is reserved for a genuinely polymorphic primitive (list_get's
# return type is whatever the list holds) -- pr_names_for_ret_type treats
# "any"-tagged primitives as a candidate for every requested type.
#
# arg_contracts is a list, one per argument position, of either "" (no
# extra contract beyond the type tag) or a predicate FUNCTION NAME that
# takes the argument's actual value (on the sample binding) and returns a
# bool -- checked BEFORE a candidate is even constructed, not after,
# pruning combinations that are provably inadmissible (e.g. a negative
# substr count) rather than building-then-rejecting them via full
# evaluation. This is deliberately unary/per-position only -- a RELATIONAL
# contract across two argument positions (e.g. "start <= text.length") is
# still enforced the way it always was, inside the try_ wrapper itself at
# evaluation time, not pruned at construction time; expressing that
# relationally at construction time is a real further improvement, not
# attempted here (see the plan's explicit non-goal on unifying this with
# the GOAP planner's own effect/precondition language).
make a function called pr_register takes registry, name, try_fn_name, arity, cost, snippets, arg_types, ret_type, arg_contracts returns done
send(registry, "set", name, ["prim", try_fn_name, arity, cost, snippets, arg_types, ret_type, arg_contracts])
let idx = get(registry, "__by_ret_type__")
if not idx then
let idx = new("Dict", "pr_by_ret_type_" + pr_next_id())
send(registry, "set", "__by_ret_type__", idx)
end
let existing = get(idx, ret_type)
if existing then
send(idx, "set", ret_type, list_push(existing, name))
else
send(idx, "set", ret_type, [name])
end
return true
end
make a function called pr_lookup takes registry, name returns entry
return get(registry, name)
end
# Every primitive/composite registered with the given ret_type, PLUS
# every one registered as "any" (a genuinely polymorphic producer) --
# lets a caller ask "what can produce a string?" instead of hand-curating
# a primitive_names list per demo, the "more realistic action set" this
# was built for.
make a function called pr_names_for_ret_type takes registry, ret_type returns names
let idx = get(registry, "__by_ret_type__")
if not idx then
return []
end
let exact = get(idx, ret_type)
if not exact then
let exact = []
end
if ret_type == "any" then
return exact
end
let poly = get(idx, "any")
if not poly then
return exact
end
return sbe_map_json_str_free(exact, poly)
end
# Plain list concatenation, named locally so this file doesn't need to
# include synthesis_by_example.patlang (which includes THIS file) just
# for sbe_list_concat.
make a function called sbe_map_json_str_free takes a, b returns out
let out = a
let i = 0
let n = to_num(list_len(b))
while i < n do
let out = list_push(out, b[i])
let i = i + 1
end
return out
end
# Checks arg_contracts (if any) for the given primitive against the
# ACTUAL VALUES a candidate call's arguments would take on the sample
# binding -- true if every declared per-position contract passes (or has
# none declared).
make a function called pr_args_satisfy_contracts takes entry, arg_values returns ok
let arg_contracts = entry[7]
let i = 0
let n = to_num(list_len(arg_contracts))
while i < n do
let contract_fn = arg_contracts[i]
if contract_fn != "" then
if not apply(contract_fn, arg_values[i]) then
return false
end
end
let i = i + 1
end
return true
end
# ---- reusable arg-contract predicates ----
make a function called pr_contract_nonneg takes v returns ok
return v >= 0
end
make a function called pr_snippet takes registry, name, lang returns tmpl
let entry = pr_lookup(registry, name)
if entry then
let snippets = entry[4]
let t = get(snippets, lang)
if t then
return t
end
end
return ""
end
make a function called pr_new_snippets returns d
return new("Dict", "primitive_snippets_" + pr_next_id())
end
make a function called pr_set_snippet takes snippets, lang, tmpl returns done
send(snippets, "set", lang, tmpl)
return true
end
# ---- try_ wrappers: the uniform [ok, value] calling convention ----
make a function called try_chr takes code returns result
if (code < 0) or (code > 1114111) then
let result = [false, ""]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, chr(code)]
ensure to_num(list_len(result)) == 2
return result
end
# char_code(s, idx) sentinel-returns -1 on an out-of-range index (verified
# in rust-runtime/src/ir/hosts.rs) rather than raising -- treated here as
# the wrapper's real, meaningful failure signal.
make a function called try_char_code takes s, idx returns result
let c = char_code(s, idx)
if c < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, c]
ensure to_num(list_len(result)) == 2
return result
end
# substr(s, start, count) clamps/saturates rather than raising (verified
# in hosts.rs) -- the manual guard below is what makes an out-of-range
# start a real, observable failure instead of a silently truncated result.
make a function called try_substr takes s, start, count returns result
if (start < 0) or (start > s.length) or (count < 0) then
let result = [false, ""]
ensure to_num(list_len(result)) == 2
return result
end
require (start >= 0) and (start <= s.length)
let result = [true, substr(s, start, count)]
ensure to_num(list_len(result)) == 2
return result
end
# String concatenation, equality, and length never fail -- always ok, kept
# in the uniform [ok, value] shape purely for the enumerator's calling
# convention.
make a function called try_concat takes a, b returns result
let result = [true, a + b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_str_eq takes a, b returns result
let result = [true, a == b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_str_len takes s returns result
let result = [true, s.length]
ensure to_num(list_len(result)) == 2
return result
end
# Wraps the existing library scan (self_hosting/lib/gherkin_contracts.
# patlang's gc_find_substr) rather than reimplementing it -- the registry
# doesn't care whether a primitive is host- or library-implemented, only
# that it has a wrapper of the uniform shape.
#
# Two variants, deliberately: try_find_substr treats "not found" as a real
# FAILURE (ok=false) -- useful when a composition should be rejected
# outright if the needle is absent. try_index_of treats "not found" as a
# perfectly valid VALUE (-1) that a later comparison can act on (e.g.
# `index_of(...) >= 0` as a presence test) -- needed because sbe_eval
# short-circuits a whole candidate to non-matching the moment any sub-call
# comes back not-ok, which would make a presence test like es_contains
# unreachable if find_substr's fail-on-absence were the only option.
make a function called try_find_substr takes hay, needle returns result
let idx = gc_find_substr(hay, needle)
if idx < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, idx]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_index_of takes hay, needle returns result
let result = [true, gc_find_substr(hay, needle)]
ensure to_num(list_len(result)) == 2
return result
end
# Search starting from a given offset (needed to find a SECOND
# occurrence of a delimiter, e.g. Markdown's closing "**" -- ordinary
# find_substr/index_of always find the FIRST occurrence from the start).
make a function called try_index_of_from takes hay, needle, start returns result
if (start < 0) or (start > hay.length) then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let rest = substr(hay, start, hay.length - start)
let found = gc_find_substr(rest, needle)
if found < 0 then
let result = [true, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, found + start]
ensure to_num(list_len(result)) == 2
return result
end
# Small arithmetic/comparison primitives -- never fail, needed so the
# enumerator can compose index arithmetic (e.g. "one past the delimiter")
# the same way it composes string operations.
make a function called try_add takes a, b returns result
let result = [true, a + b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_sub takes a, b returns result
let result = [true, a - b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_geq takes a, b returns result
let result = [true, a >= b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_gt takes a, b returns result
let result = [true, a > b]
ensure to_num(list_len(result)) == 2
return result
end
# cond(test, a, b) -> a if test else b. Never fails; deliberately doesn't
# type-check a/b against each other -- it just returns whichever branch
# the caller asked for. This is what lets the enumerator express genuine
# conditional SELECTION (as opposed to the separate decision-list mode's
# literal-equality branching) as an ordinary Call node, without adding a
# new AST node kind: "which of two already-computed values is the right
# one" becomes composable the same way any other primitive is.
# PatLang has no inline ternary expression, only an `if` statement -- this
# is the plain-function equivalent used by "cond"'s own emitted call-site
# snippet (sbe_pat_cond({0}, {1}, {2})), so generated source that includes
# this file can actually call the emitted expression.
make a function called sbe_pat_cond takes test, a, b returns result
if test then
return a
end
return b
end
make a function called try_cond takes test, a, b returns result
if test then
let result = [true, a]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, b]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_eq_int takes a, b returns result
let result = [true, a == b]
ensure to_num(list_len(result)) == 2
return result
end
# list_get(xs, idx) returns Unit/empty on an out-of-range index rather
# than raising (verified in rust-runtime/src/ir/hosts.rs) -- the manual
# guard below is what makes an out-of-range index a real, observable
# failure instead of an ambiguous "empty" result.
make a function called try_list_get takes xs, idx returns result
if (idx < 0) or (idx >= to_num(list_len(xs))) then
let result = [false, ""]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, list_get(xs, idx)]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_list_len takes xs returns result
let result = [true, to_num(list_len(xs))]
ensure to_num(list_len(result)) == 2
return result
end
# ---- effectful primitives: same uniform shape, same contract discipline.
# tcp_try_connect/tcp_try_listen already exist at the host level (the
# "real try_ pairing" case) -- these wrappers just normalize their
# -1-on-failure sentinel into the same [ok, value] convention every other
# registrant uses, so the enumerator never has to special-case them.
make a function called try_tcp_connect takes host, port returns result
let id = tcp_try_connect(host, port)
if id < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, id]
ensure to_num(list_len(result)) == 2
return result
end
make a function called try_tcp_listen takes port returns result
let id = tcp_try_listen(port)
if id < 0 then
let result = [false, -1]
ensure to_num(list_len(result)) == 2
return result
end
let result = [true, id]
ensure to_num(list_len(result)) == 2
return result
end
# ---- the standard registry: every primitive above, registered with its
# arity, a search cost, and a per-language snippet dictionary. "patlang"
# is always present (its template is just the real primitive call text);
# other languages are added incrementally, one snippet at a time, per
# primitive -- adding a new target language never requires a new
# per-node-kind transpiler (contrast self_hosting/lib/transpile_ruby.
# patlang's whole-AST walker), just one template per primitive you want
# callable from it.
make a function called pr_standard_registry returns registry
let registry = pr_new_registry()
let s_chr = pr_new_snippets()
pr_set_snippet(s_chr, "patlang", "chr({0})")
pr_set_snippet(s_chr, "ruby", "({0}).chr")
pr_set_snippet(s_chr, "python", "chr({0})")
pr_register(registry, "chr", "try_chr", 1, 1, s_chr, ["int"], "string", [""])
let s_char_code = pr_new_snippets()
pr_set_snippet(s_char_code, "patlang", "char_code({0}, {1})")
pr_set_snippet(s_char_code, "ruby", "({0}).getbyte({1})")
pr_set_snippet(s_char_code, "python", "ord({0}[{1}])")
pr_register(registry, "char_code", "try_char_code", 2, 1, s_char_code, ["string", "int"], "int", ["", "pr_contract_nonneg"])
let s_substr = pr_new_snippets()
pr_set_snippet(s_substr, "patlang", "substr({0}, {1}, {2})")
pr_set_snippet(s_substr, "ruby", "({0})[{1}, {2}]")
pr_set_snippet(s_substr, "python", "({0})[{1}:{1}+{2}]")
pr_register(registry, "substr", "try_substr", 3, 1, s_substr, ["string", "int", "int"], "string", ["", "pr_contract_nonneg", "pr_contract_nonneg"])
let s_concat = pr_new_snippets()
pr_set_snippet(s_concat, "patlang", "({0} + {1})")
pr_set_snippet(s_concat, "ruby", "({0} + {1})")
pr_set_snippet(s_concat, "python", "({0} + {1})")
pr_register(registry, "concat", "try_concat", 2, 1, s_concat, ["string", "string"], "string", ["", ""])
let s_str_eq = pr_new_snippets()
pr_set_snippet(s_str_eq, "patlang", "({0} == {1})")
pr_set_snippet(s_str_eq, "ruby", "({0} == {1})")
pr_set_snippet(s_str_eq, "python", "({0} == {1})")
pr_register(registry, "str_eq", "try_str_eq", 2, 1, s_str_eq, ["string", "string"], "bool", ["", ""])
let s_str_len = pr_new_snippets()
pr_set_snippet(s_str_len, "patlang", "({0}).length")
pr_set_snippet(s_str_len, "ruby", "({0}).length")
pr_set_snippet(s_str_len, "python", "len({0})")
pr_register(registry, "str_len", "try_str_len", 1, 1, s_str_len, ["string"], "int", [""])
let s_find_substr = pr_new_snippets()
pr_set_snippet(s_find_substr, "patlang", "gc_find_substr({0}, {1})")
pr_set_snippet(s_find_substr, "ruby", "(({0}).index({1}) or -1)")
pr_set_snippet(s_find_substr, "python", "({0}).find({1})")
pr_register(registry, "find_substr", "try_find_substr", 2, 1, s_find_substr, ["string", "string"], "int", ["", ""])
let s_index_of = pr_new_snippets()
pr_set_snippet(s_index_of, "patlang", "gc_find_substr({0}, {1})")
pr_set_snippet(s_index_of, "ruby", "(({0}).index({1}) or -1)")
pr_set_snippet(s_index_of, "python", "({0}).find({1})")
pr_register(registry, "index_of", "try_index_of", 2, 1, s_index_of, ["string", "string"], "int", ["", ""])
# NOTE: this call-site template is only correct when the needle IS
# found (it doesn't special-case gc_find_substr's -1-not-found sentinel
# the way try_index_of_from itself does) -- fine for emitting source
# that's only ever run on inputs already known (via the examples that
# proved it) to contain a match; not used by sbe_eval's own direct
# evaluation path, which always calls the real try_ function.
let s_index_of_from = pr_new_snippets()
pr_set_snippet(s_index_of_from, "patlang", "(gc_find_substr(substr({0}, {2}, ({0}).length - {2}), {1}) + {2})")
pr_register(registry, "index_of_from", "try_index_of_from", 3, 2, s_index_of_from, ["string", "string", "int"], "int", ["", "", "pr_contract_nonneg"])
let s_add = pr_new_snippets()
pr_set_snippet(s_add, "patlang", "({0} + {1})")
pr_set_snippet(s_add, "ruby", "({0} + {1})")
pr_set_snippet(s_add, "python", "({0} + {1})")
pr_register(registry, "add", "try_add", 2, 1, s_add, ["int", "int"], "int", ["", ""])
let s_sub = pr_new_snippets()
pr_set_snippet(s_sub, "patlang", "({0} - {1})")
pr_set_snippet(s_sub, "ruby", "({0} - {1})")
pr_set_snippet(s_sub, "python", "({0} - {1})")
pr_register(registry, "sub", "try_sub", 2, 1, s_sub, ["int", "int"], "int", ["", ""])
let s_geq = pr_new_snippets()
pr_set_snippet(s_geq, "patlang", "({0} >= {1})")
pr_set_snippet(s_geq, "ruby", "({0} >= {1})")
pr_set_snippet(s_geq, "python", "({0} >= {1})")
pr_register(registry, "geq", "try_geq", 2, 1, s_geq, ["int", "int"], "bool", ["", ""])
let s_gt = pr_new_snippets()
pr_set_snippet(s_gt, "patlang", "({0} > {1})")
pr_set_snippet(s_gt, "ruby", "({0} > {1})")
pr_set_snippet(s_gt, "python", "({0} > {1})")
pr_register(registry, "gt", "try_gt", 2, 1, s_gt, ["int", "int"], "bool", ["", ""])
let s_cond = pr_new_snippets()
pr_set_snippet(s_cond, "patlang", "sbe_pat_cond({0}, {1}, {2})")
pr_register(registry, "cond", "try_cond", 3, 1, s_cond, ["bool", "any", "any"], "any", ["", "", ""])
let s_eq_int = pr_new_snippets()
pr_set_snippet(s_eq_int, "patlang", "({0} == {1})")
pr_set_snippet(s_eq_int, "ruby", "({0} == {1})")
pr_set_snippet(s_eq_int, "python", "({0} == {1})")
pr_register(registry, "eq_int", "try_eq_int", 2, 1, s_eq_int, ["int", "int"], "bool", ["", ""])
let s_list_get = pr_new_snippets()
pr_set_snippet(s_list_get, "patlang", "list_get({0}, {1})")
pr_set_snippet(s_list_get, "ruby", "({0})[{1}]")
pr_set_snippet(s_list_get, "python", "({0})[{1}]")
pr_register(registry, "list_get", "try_list_get", 2, 1, s_list_get, ["list", "int"], "any", ["", "pr_contract_nonneg"])
let s_list_len = pr_new_snippets()
pr_set_snippet(s_list_len, "patlang", "to_num(list_len({0}))")
pr_set_snippet(s_list_len, "ruby", "({0}).length")
pr_set_snippet(s_list_len, "python", "len({0})")
pr_register(registry, "list_len", "try_list_len", 1, 1, s_list_len, ["list"], "int", [""])
let s_tcp_connect = pr_new_snippets()
pr_set_snippet(s_tcp_connect, "patlang", "tcp_try_connect({0}, {1})")
pr_register(registry, "tcp_connect", "try_tcp_connect", 2, 5, s_tcp_connect, ["string", "int"], "int", ["", "pr_contract_nonneg"])
let s_tcp_listen = pr_new_snippets()
pr_set_snippet(s_tcp_listen, "patlang", "tcp_try_listen({0})")
pr_register(registry, "tcp_listen", "try_tcp_listen", 1, 5, s_tcp_listen, ["int"], "int", ["pr_contract_nonneg"])
return registry
end
# ---- evaluator ----
#
# Dispatches a Call node to its registry entry's real implementation --
# either a Layer-1 try_ wrapper (kind "prim") or a previously-derived
# composite's own stored AST (kind "composite", see register_composite
# below), replaying that composite's parameter bindings the same way a
# real function call would. If any sub-call comes back not-ok, the WHOLE
# candidate is rejected for that example (returned as [false, ...]) rather
# than aborting the search -- this is exactly why every Layer-1 wrapper is
# non-fatal (plain `if`, never a fatal require) on its real failure path.
make a function called sbe_call_prim takes try_fn, vals returns result
let n = to_num(list_len(vals))
if n == 0 then
return apply(try_fn)
end
if n == 1 then
return apply(try_fn, vals[0])
end
if n == 2 then
return apply(try_fn, vals[0], vals[1])
end
if n == 3 then
return apply(try_fn, vals[0], vals[1], vals[2])
end
if n == 4 then
return apply(try_fn, vals[0], vals[1], vals[2], vals[3])
end
return [false, "sbe_call_prim: unsupported arity " + n]
end
make a function called sbe_eval takes node, bindings, registry returns result
let tag = node[0]
if tag == "Const" then
return [true, node[1]]
end
if tag == "Input" then
return [true, get(bindings, node[1])]
end
if tag == "If" then
let cond = sbe_eval(node[1], bindings, registry)
if cond[0] == false then
return [false, ""]
end
if cond[1] then
return sbe_eval(node[2], bindings, registry)
end
return sbe_eval(node[3], bindings, registry)
end
if tag == "Call" then
let prim = node[1]
let arg_nodes = node[2]
let entry = pr_lookup(registry, prim)
if not entry then
return [false, ""]
end
let n = to_num(list_len(arg_nodes))
let vals = []
let all_ok = true
let i = 0
while i < n do
let sub = sbe_eval(arg_nodes[i], bindings, registry)
if sub[0] == false then
let all_ok = false
end
let vals = list_push(vals, sub[1])
let i = i + 1
end
if all_ok == false then
return [false, ""]
end
let kind = entry[0]
let impl = entry[1]
if kind == "prim" then
return sbe_call_prim(impl, vals)
end
# kind == "composite": impl = [inner_ast, param_names] -- replay the
# derived function's own body against ITS OWN parameter names, the
# same way any ordinary function call binds formal parameters.
let inner_ast = impl[0]
let param_names = impl[1]
let inner_bindings = new("Dict", "sbe_bind_" + pr_next_id())
let j = 0
while j < n do
send(inner_bindings, "set", param_names[j], vals[j])
let j = j + 1
end
return sbe_eval(inner_ast, inner_bindings, registry)
end
return [false, "sbe_eval: unknown node tag"]
end
# ---- size, filtering, candidate construction ----
make a function called sbe_size takes node returns n
let tag = node[0]
if tag == "Call" then
let args = node[2]
let total = 1
let i = 0
let m = to_num(list_len(args))
while i < m do
let total = total + sbe_size(args[i])
let i = i + 1
end
return total
end
if tag == "If" then
return 1 + sbe_size(node[1]) + sbe_size(node[2]) + sbe_size(node[3])
end
return 1
end
# Every candidate AST is tracked as a TYPED node [ast, size, type, value]
# once built -- `type` is type_of(...) of that AST's value when evaluated
# against a representative example's bindings ("int"/"string"/"bool", or
# "invalid" if that evaluation itself came back not-ok); `value` is that
# same computed value, kept alongside so a primitive's arg_contracts can
# be checked against it later without re-evaluating. This typing is
# required, not just an optimization: PatLang raises a FATAL interpreter
# error on a type-mismatched comparison (`code < 0` on a string aborts
# the whole process, confirmed empirically -- there is no try/catch to
# recover from it), so the search must know an argument's type BEFORE
# ever constructing a call with it, never discover a mismatch by
# attempting one.
make a function called sbe_infer_type_and_value takes node, registry, sample_bindings returns pair
let r = sbe_eval(node, sample_bindings, registry)
if r[0] == false then
return ["invalid", ""]
end
return [type_of(r[1]), r[1]]
end
make a function called sbe_wrap takes node, registry, sample_bindings returns typed
let tv = sbe_infer_type_and_value(node, registry, sample_bindings)
return [node, sbe_size(node), tv[0], tv[1]]
end
# ---- the candidate pool INDEX: a real (type -> size -> bucket) tree,
# not a flat list scanned on every lookup. sbe_build_calls used to call a
# linear-scan filter once per (primitive, argument position, size
# partition) -- with the pool itself growing multiplicatively every
# level, that repeated O(pool) scan compounded the blowup on top of the
# search space's own genuine growth (measured directly: a flat,
# non-decomposed search on replace_in_text grew from a 12s level to a
# 165s level across 3 levels, growing FASTER than the pool itself). This
# index turns "every size-5 string-typed node" into a couple of Dict
# lookups instead of a scan of everything ever built.
make a function called sbe_index_new returns index
return new("Dict", "sbe_index_" + pr_next_id())
end
make a function called sbe_index_add takes index, typed returns done
let ty = typed[2]
let size = typed[1]
let by_size = get(index, ty)
if not by_size then
let by_size = new("Dict", "sbe_index_bysize_" + pr_next_id())
send(index, "set", ty, by_size)
end
let size_key = "" + size
let bucket = get(by_size, size_key)
if not bucket then
let bucket = []
end
send(by_size, "set", size_key, list_push(bucket, typed))
return true
end
# Stores an entire (type, size) bucket in ONE Dict write. Only ever
# called with a size that has never been written for this type before
# (each level only ever produces nodes of exactly the current size, and
# sizes strictly increase), so this never has to merge with an existing
# bucket -- the caller (synthesize_from_examples) accumulates a level's
# new nodes in a plain LOCAL list first (cheap: a uniquely-held list, not
# aliased into any Dict, so list_push there is a genuine in-place O(1)
# amortized append -- see rust-runtime/src/ir/hosts.rs's own comment on
# host_list_push's Arc::make_mut: pushing onto a list some OTHER live
# reference still shares forces a full deep clone). Calling sbe_index_add
# once PER CANDIDATE during a level, instead of batching like this, was
# measured to make the search SLOWER than the original flat scan it was
# meant to replace -- every such call re-reads the bucket already stored
# in the Dict (aliasing its Arc), so the very next list_push onto it has
# to deep-clone the whole bucket first, turning insertion into O(bucket
# size) per candidate instead of O(1).
make a function called sbe_index_set_bucket takes index, ty, size, items returns done
let by_size = get(index, ty)
if not by_size then
let by_size = new("Dict", "sbe_index_bysize_" + pr_next_id())
send(index, "set", ty, by_size)
end
send(by_size, "set", "" + size, items)
return true
end
make a function called sbe_index_lookup takes index, size, ty returns bucket
let by_size = get(index, ty)
if not by_size then
return []
end
let bucket = get(by_size, "" + size)
if not bucket then
return []
end
return bucket
end
# ---- sliding-window memory bound (Design B) ----
#
# The index otherwise retains every surviving candidate from every level
# ever explored, unboundedly -- confirmed directly as the real memory
# driver behind GitHub issue #73 (the first_exceeding two-list case
# climbed past 20GB+ and kept growing well before finding a match).
# Parallelizing evaluation (Design A) only ever addressed wall-clock
# time, not this. Only the most recent `sbe_window_size()` composed
# levels are kept; older ones are evicted by overwriting their bucket
# with an empty list (no delete primitive needed -- sbe_index_lookup
# already treats empty and missing the same way, and dropping the last
# reference to the old list lets it actually be freed).
#
# Leaves (size 1 -- Input/Const) are NEVER evicted: they're cheap (a
# small, fixed set per search) and are exactly what a late-level
# candidate most often reaches back for -- confirmed directly in the
# actual first_exceeding formula this was built to fix, which reused
# list_get(xs, 1) (built from two size-1 leaves) deep inside a
# size-17+ AST. Windowing sizes >= 2 only, while keeping every leaf,
# is a real completeness/memory tradeoff, not a free lunch: a solution
# that needs a specific size-3+ intermediate piece combined only many
# levels later than the window allows could still be missed. State that
# plainly wherever this is described, not just here.
#
# 16, not 8: confirmed by real evidence, not picked in the abstract. The
# real first_exceeding two-list case (the one that originally hit
# GitHub issue #73's 45GB+ figure) genuinely needed a window this size --
# window=8 completed safely (no crash, no resource risk) but returned
# ERR, evicting a piece (list_get(xs,0)/list_get(xs,1), each reused deep
# in the winning AST) the TRUE general formula needed; window=16
# (effectively unbounded for this problem's own depth) found the exact
# same case's genuinely correct, non-overfit answer in ~53 minutes with
# memory staying healthy throughout (peaked well under what the
# unbounded/unchunked version needed, and ended with 45GB still free).
# A too-small window doesn't fail loudly -- it fails by returning a
# confident ERR for a solvable problem, which is worth remembering
# before treating a smaller window as a safe default for a new domain.
make a function called sbe_window_size returns w
let override = get("__vars", "sbe_window_size_override")
if override then
return to_num(override)
end
return 16
end
make a function called sbe_evict_size takes index, size returns done
if size < 2 then
return true
end
let types = sbe_concrete_types()
let t = 0
let tn = to_num(list_len(types))
while t < tn do
let by_size = get(index, types[t])
if by_size then
send(by_size, "set", "" + size, [])
end
let t = t + 1
end
return true
end
# The (size, type)-indexed bucket, ALSO filtered by a single-argument
# contract (self_hosting/lib/primitive_registry.patlang's arg_contracts)
# checked against each candidate's already-computed value -- so a
# provably-inadmissible argument (e.g. a negative substr count) is
# dropped before it's ever combined into a Call node, not generated then
# rejected by full evaluation. Returns raw AST nodes (the Call node needs
# the ast, not the bookkeeping).
# The 4 concrete runtime types sbe_infer_type_and_value can ever produce
# (never "any" -- that's a registry-declared wildcard, not a real
# runtime type, see primitive_registry.patlang's own note on this).
make a function called sbe_concrete_types returns tys
return ["int", "string", "bool", "list"]
end
# "any" argument position (e.g. cond's 2nd/3rd args): union every
# concrete type's bucket at this size, contract-filtered the same way a
# single concrete type would be -- lets a primitive genuinely accept a
# value of whatever type, needed for real conditional SELECTION (return
# whichever of two already-computed values a test picks) without the
# type system rejecting it outright.
make a function called sbe_index_lookup_filtered_any takes index, size, contract_fn returns out
let out = []
let types = sbe_concrete_types()
let t = 0
let tn = to_num(list_len(types))
while t < tn do
let out = sbe_list_concat(out, sbe_index_lookup_filtered(index, size, types[t], contract_fn))
let t = t + 1
end
return out
end
make a function called sbe_index_lookup_filtered takes index, size, ty, contract_fn returns out
if ty == "any" then
return sbe_index_lookup_filtered_any(index, size, contract_fn)
end
let bucket = sbe_index_lookup(index, size, ty)
if contract_fn == "" then
let out = []
let i = 0
let n = to_num(list_len(bucket))
while i < n do
let out = list_push(out, bucket[i][0])
let i = i + 1
end
return out
end
let out = []
let i = 0
let n = to_num(list_len(bucket))
while i < n do
let typed = bucket[i]
if apply(contract_fn, typed[3]) then
let out = list_push(out, typed[0])
end
let i = i + 1
end
return out
end
# All Call nodes of exactly target_size for a primitive with the given
# per-position arg_types/arg_contracts, drawing arguments from the INDEX
# (any smaller, type-tagged node already built), by partitioning
# target_size - 1 (the budget left after paying 1 for the Call itself)
# across the primitive's argument positions -- each position looked up
# directly by (size, type) and pruned by its own arg_contract, rather
# than scanned out of a flat pool. Only arities 1-3 are needed by the
# registered primitive set.
make a function called sbe_arg_types_has_any takes arg_types returns yes
let i = 0
let n = to_num(list_len(arg_types))
while i < n do
if arg_types[i] == "any" then
return true
end
let i = i + 1
end
return false
end
make a function called sbe_resolve_any_types takes arg_types, concrete returns out
let out = []
let i = 0
let n = to_num(list_len(arg_types))
while i < n do
if arg_types[i] == "any" then
let out = list_push(out, concrete)
else
let out = list_push(out, arg_types[i])
end
let i = i + 1
end
return out
end
# A call with more than one "any" position (e.g. cond(test, a, b)'s two
# branches) must have EVERY "any" position resolve to the SAME concrete
# type together, not independently -- resolving them independently once
# let a candidate's two branches be different types (say int and bool),
# which is exactly how a single-example-derived type tag went stale on a
# later example with a different test outcome, crashing a downstream
# comparison with a real "type error in cmp" (confirmed directly while
# building the first_exceeding worked example). Only "any" itself is
# ever ambiguous this way -- every other declared type is fixed
# regardless of value, so this loop is skipped entirely (zero behavior
# change) for every primitive that doesn't use "any".
#
# `target_size`/`size` throughout this file means each registered
# primitive's own declared COST (primitive_registry.patlang's
# pr_register 5th arg), not a flat "1 call = 1 unit" node count -- found
# and fixed as a real latent bug (GitHub issue #71's closing
# investigation, self_hosting/lib/fact_relaxation_synthesis.patlang):
# most primitives happen to cost 1, but index_of_from costs 2 and
# tcp_connect costs 5, and this function used to hardcode `rem =
# target_size - 1` regardless, silently ignoring registered cost
# whenever it wasn't 1 -- "smallest wins" was really "fewest AST nodes
# wins". `prim_cost` (the calling primitive's own registered cost,
# looked up once by the caller) replaces that hardcoded 1.
make a function called sbe_build_calls takes prim, arg_types, arg_contracts, target_size, index, prim_cost returns out
if sbe_arg_types_has_any(arg_types) then
let out = []
let types = sbe_concrete_types()
let t = 0
let tn = to_num(list_len(types))
while t < tn do
let resolved = sbe_resolve_any_types(arg_types, types[t])
let out = sbe_list_concat(out, sbe_build_calls(prim, resolved, arg_contracts, target_size, index, prim_cost))
let t = t + 1
end
return out
end
let out = []
let rem = target_size - prim_cost
let arity = to_num(list_len(arg_types))
if arity == 1 then
if rem >= 1 then
let group = sbe_index_lookup_filtered(index, rem, arg_types[0], arg_contracts[0])
let i = 0
let n = to_num(list_len(group))
while i < n do
let out = list_push(out, ["Call", prim, [group[i]]])
let i = i + 1
end
end
return out
end
if arity == 2 then
let a = 1
while a <= rem - 1 do
let b = rem - a
let ga = sbe_index_lookup_filtered(index, a, arg_types[0], arg_contracts[0])
let gb = sbe_index_lookup_filtered(index, b, arg_types[1], arg_contracts[1])
let i = 0
let ni = to_num(list_len(ga))
while i < ni do
let j = 0
let nj = to_num(list_len(gb))
while j < nj do
let out = list_push(out, ["Call", prim, [ga[i], gb[j]]])
let j = j + 1
end
let i = i + 1
end
let a = a + 1
end
return out
end
if arity == 3 then
let a = 1
while a <= rem - 2 do
let b = 1
while b <= rem - a - 1 do
let c = rem - a - b
let ga = sbe_index_lookup_filtered(index, a, arg_types[0], arg_contracts[0])
let gb = sbe_index_lookup_filtered(index, b, arg_types[1], arg_contracts[1])
let gc = sbe_index_lookup_filtered(index, c, arg_types[2], arg_contracts[2])
let i = 0
let ni = to_num(list_len(ga))
while i < ni do
let j = 0
let nj = to_num(list_len(gb))
while j < nj do
let k = 0
let nk = to_num(list_len(gc))
while k < nk do
let out = list_push(out, ["Call", prim, [ga[i], gb[j], gc[k]]])
let k = k + 1
end
let j = j + 1
end
let i = i + 1
end
let b = b + 1
end
let a = a + 1
end
return out
end
if arity == 4 then
let a = 1
while a <= rem - 3 do
let b = 1
while b <= rem - a - 2 do
let c = 1
while c <= rem - a - b - 1 do
let d = rem - a - b - c
let ga = sbe_index_lookup_filtered(index, a, arg_types[0], arg_contracts[0])
let gb = sbe_index_lookup_filtered(index, b, arg_types[1], arg_contracts[1])
let gc = sbe_index_lookup_filtered(index, c, arg_types[2], arg_contracts[2])
let gd = sbe_index_lookup_filtered(index, d, arg_types[3], arg_contracts[3])
let i = 0
let ni = to_num(list_len(ga))
while i < ni do
let j = 0
let nj = to_num(list_len(gb))
while j < nj do
let k = 0
let nk = to_num(list_len(gc))
while k < nk do
let l = 0
let nl = to_num(list_len(gd))
while l < nl do
let out = list_push(out, ["Call", prim, [ga[i], gb[j], gc[k], gd[l]]])
let l = l + 1
end
let k = k + 1
end
let j = j + 1
end
let i = i + 1
end
let c = c + 1
end
let b = b + 1
end
let a = a + 1
end
return out
end
return out
end
make a function called sbe_matches_all takes node, examples, registry returns ok
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let result = sbe_eval(node, ex[0], registry)
if result[0] == false then
return false
end
if result[1] != ex[1] then
return false
end
let i = i + 1
end
return true
end
# Observational-equivalence key: two candidates that produce the exact
# same [ok, value] outcome across every example are interchangeable for
# search purposes -- keeping only the first (smallest) one found is the
# same pruning classic enumerative synthesis engines use to stay
# tractable.
make a function called sbe_output_key takes node, examples, registry returns key
let key = sb_new()
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let result = sbe_eval(node, ex[0], registry)
if result[0] then
sb_push(key, "1:" + ("" + result[1]))
else
sb_push(key, "0")
end
sb_push(key, "|")
let i = i + 1
end
return sb_str(key)
end
make a function called sbe_list_concat takes a, b returns out
let out = a
let i = 0
let n = to_num(list_len(b))
while i < n do
let out = list_push(out, b[i])
let i = i + 1
end
return out
end
make a function called sbe_seed_leaves takes input_names, const_values returns out
let out = []
let i = 0
let n = to_num(list_len(input_names))
while i < n do
let out = list_push(out, ["Input", input_names[i]])
let i = i + 1
end
let i = 0
let n = to_num(list_len(const_values))
while i < n do
let out = list_push(out, ["Const", const_values[i]])
let i = i + 1
end
return out
end
# A small, DOCUMENTED curated constant pool, not the full 0-255 byte range:
# the plan's original "0-255" idea would blow up the level-2 combinatorics
# (every Call argument slot drawn from this pool) to hundreds of millions
# of candidates for a 2-3 argument primitive. Covers the separators/counts
# actually needed by ASCII text parsing (CR/LF/space/tab, and small
# offsets like "one past a delimiter"); callers needing a different pool
# (e.g. a specific separator string) pass it via `extra_consts`.
make a function called sbe_default_int_consts returns cs
return [0, 1, 2, 3, 9, 10, 13, 32]
end
# ---- parallel candidate evaluation ----
#
# Each candidate's evaluation (does it match every example? what's its
# observational-equivalence key? what type/value does it produce?) is
# pure and independent of every other candidate's -- the confirmed real
# bottleneck (measured directly: ~250,000 independent evaluations at one
# level of the first_exceeding search, see the site page's worked
# example) is exactly the shape parallel_map (rust-runtime/src/ir/
# interpreter.rs's real-OS-thread map, not a fiber) is for. This worker
# is a plain top-level function, not a closure, because parallel_map
# calls it as `name(item)` on a fresh Interpreter per thread with no
# access to synthesize_from_examples's own locals -- examples/registry/
# sample_bindings are fetched from __vars instead, which PatLang's
# object store already guarantees is shared across every OS thread
# (confirmed: it's a single process-wide Mutex-protected map, not
# per-interpreter state). The SAME worker is used for the sequential
# fallback below max_size threshold too, so both paths share one
# implementation and can never silently diverge in behavior.
make a function called sbe_eval_candidate_worker takes node returns result
let examples = get("__vars", "sbe_par_examples")
let registry = get("__vars", "sbe_par_registry")
let sample_bindings = get("__vars", "sbe_par_sample_bindings")
let ok = sbe_matches_all(node, examples, registry)
let key = sbe_output_key(node, examples, registry)
let typed = sbe_wrap(node, registry, sample_bindings)
return [ok, key, typed[2], typed[3]]
end
# Below this many candidates, thread-spawn overhead would cost more than
# it saves (confirmed: sizes 2-8 typically have dozens to low hundreds of
# candidates and already finish in well under a second sequentially).
make a function called sbe_parallel_threshold returns n
return 300
end
# parallel_map spawns one real OS thread PER ITEM it's given (rust-
# runtime/src/ir/interpreter.rs:346-361's std::thread::scope loop) --
# fine for a bounded list, but a candidate list at size 14+ can run into
# the tens of thousands, and spawning that many threads AT ONCE causes
# real OS-level scheduling contention (confirmed directly: the whole
# machine, not just this process, became sluggish -- not a memory or
# per-process CPU symptom, a thread-count one). Fixed by chunking:
# split the candidate list into a small, FIXED number of chunks
# (matching real core count, not the candidate count), and parallel_map
# over the CHUNKS -- each chunk's own candidates are evaluated
# sequentially, within that one thread, by sbe_eval_candidate_chunk_worker.
make a function called sbe_parallel_chunk_count returns n
return 20
end
make a function called sbe_chunk_list takes items, num_chunks returns chunks
let n = to_num(list_len(items))
let chunks = []
if n == 0 then
return chunks
end
let chunk_size = to_num(floor((n + num_chunks - 1) / num_chunks))
if chunk_size < 1 then
let chunk_size = 1
end
let i = 0
while i < n do
let stop = i + chunk_size
if stop > n then
let stop = n
end
let chunk = []
let j = i
while j < stop do
let chunk = list_push(chunk, items[j])
let j = j + 1
end
let chunks = list_push(chunks, chunk)
let i = stop
end
return chunks
end
make a function called sbe_eval_candidate_chunk_worker takes chunk returns results
let results = []
let i = 0
let n = to_num(list_len(chunk))
while i < n do
let results = list_push(results, sbe_eval_candidate_worker(chunk[i]))
let i = i + 1
end
return results
end
make a function called sbe_evaluate_candidates takes candidates, examples, registry, sample_bindings returns results
set_var("sbe_par_examples", examples)
set_var("sbe_par_registry", registry)
set_var("sbe_par_sample_bindings", sample_bindings)
let cn = to_num(list_len(candidates))
if cn > sbe_parallel_threshold() then
let chunks = sbe_chunk_list(candidates, sbe_parallel_chunk_count())
let chunk_results = parallel_map(chunks, "sbe_eval_candidate_chunk_worker")
# Flatten in order -- parallel_map preserves input order, and each
# chunk's own results are already in-order (sequential within it),
# so a straight concatenation reconstructs candidates' original order.
let results = []
let k = 0
let kn = to_num(list_len(chunk_results))
while k < kn do
let results = sbe_list_concat(results, chunk_results[k])
let k = k + 1
end
return results
end
let results = []
let c = 0
while c < cn do
let results = list_push(results, sbe_eval_candidate_worker(candidates[c]))
let c = c + 1
end
return results
end
# ---- the bottom-up search ----
#
# Returns ["OK", ast] for the smallest AST (by node count) that reproduces
# every example exactly, searched in strictly increasing size order so the
# first match found IS the smallest, or ["ERR", msg] if none exists up to
# max_size.
# ---- diagnostics ----
#
# The exponential blow-up measured on a flat, non-decomposed search (see
# the plan/session notes on replace_in_text) and the "constant trap"/
# "algebraic coincidence" pitfalls found repeatedly across this session's
# demos (after_space, tail_after, inner_text -- always because too few
# examples let a smaller, wrong candidate through) are the SAME kind of
# signal in both directions: the search itself already has the data to
# tell a BDD author "this spec needs splitting" (sustained fast pool
# growth) or "this spec needs another example" (more than one
# structurally different, equally-minimal candidate satisfies it) --
# rather than that only ever being noticed after the fact by a human
# staring at a suspicious-looking AST. These notes are advisory only
# (appended as a 3rd list element every existing caller already ignores,
# since none of them look past result[0]/result[1]).
make a function called sbe_growth_note takes size, ratio returns note
return "search pool grew " + to_fixed(ratio, 1) + "x at size " + size + " (sustained fast growth) -- if this gets slow, consider decomposing the target into smaller, independently-specified composites (see how after_space/take_before/take_after/splice were split out of replace_in_text)"
end
make a function called sbe_ambiguity_note takes alt_count, size returns note
return "" + alt_count + " other structurally different candidate(s) of the same minimal size (" + size + ") also satisfy every given example -- if the intended behavior is more specific than what's shown, add a disambiguating example (the same fix that ruled out after_space's substr-clamp shortcut and inner_text's reused-length shortcut)"
end
make a function called synthesize_from_examples takes examples, input_names, extra_consts, registry, primitive_names, max_size returns result
let consts = sbe_list_concat(sbe_default_int_consts(), extra_consts)
let sample_bindings = examples[0][0]
let leaves = sbe_seed_leaves(input_names, consts)
let index = sbe_index_new()
let seen = new("Dict", "sbe_seen_" + pr_next_id())
let pool_count = 0
let notes = []
let high_growth_streak = 0
let winner = ["Const", ""]
let found_match = false
let alt_count = 0
let i = 0
let n = to_num(list_len(leaves))
while i < n do
let node = leaves[i]
if sbe_matches_all(node, examples, registry) then
if found_match then
let alt_count = alt_count + 1
else
let found_match = true
let winner = node
end
end
let key = sbe_output_key(node, examples, registry)
if not get(seen, key) then
send(seen, "set", key, true)
sbe_index_add(index, sbe_wrap(node, registry, sample_bindings))
let pool_count = pool_count + 1
end
let i = i + 1
end
if found_match then
if alt_count > 0 then
let notes = list_push(notes, sbe_ambiguity_note(alt_count, 1))
end
return ["OK", winner, notes]
end
let size = 2
while size <= max_size do
print("synthesize_from_examples: size=" + size + " pool=" + pool_count + " at " + now_ms())
let pool_before_level = pool_count
# Accumulate this level's newly-accepted candidates in plain LOCAL
# lists, one per runtime type, grouped by hand rather than through
# the Dict-backed index -- every candidate this level shares the same
# `size`, so each of these lists becomes exactly one brand-new bucket
# merged into the index ONCE at the end of the level (via
# sbe_index_set_bucket), instead of once per candidate. A uniquely-
# held local list's list_push is a genuine O(1) amortized append;
# reading a bucket back out of the index mid-level and pushing onto
# THAT would alias its stored Arc and force a full deep clone on
# every single push (measured directly: doing it that way made this
# search slower than the flat scan it was meant to replace).
let level_int = []
let level_string = []
let level_bool = []
let level_list = []
let winner = ["Const", ""]
let found_match = false
let alt_count = 0
let p = 0
let pn = to_num(list_len(primitive_names))
while p < pn do
let prim = primitive_names[p]
let entry = pr_lookup(registry, prim)
if entry then
let arg_types = entry[5]
let arg_contracts = entry[7]
let prim_cost = to_num(entry[3])
let candidates = sbe_build_calls(prim, arg_types, arg_contracts, size, index, prim_cost)
let cn = to_num(list_len(candidates))
let results = sbe_evaluate_candidates(candidates, examples, registry, sample_bindings)
# Sequential reduce pass -- cheap bookkeeping only, since the
# expensive per-candidate work already happened above (in
# parallel, once cn is large enough). Iterated by index so the
# exact same logic serves both the parallel and sequential paths
# from sbe_evaluate_candidates, and so "first match in original
# order wins" stays deterministic regardless of which path ran.
let c = 0
while c < cn do
let node = candidates[c]
let r = results[c]
let ok = r[0]
let key = r[1]
let ty = r[2]
let value = r[3]
if ok then
if found_match then
let alt_count = alt_count + 1
else
let found_match = true
let winner = node
end
end
let already = get(seen, key)
if not already then
send(seen, "set", key, true)
let typed = [node, size, ty, value]
if ty == "int" then
let level_int = list_push(level_int, typed)
else
if ty == "string" then
let level_string = list_push(level_string, typed)
else
if ty == "bool" then
let level_bool = list_push(level_bool, typed)
else
if ty == "list" then
let level_list = list_push(level_list, typed)
end
end
end
end
let pool_count = pool_count + 1
end
let c = c + 1
end
end
let p = p + 1
end
if to_num(list_len(level_int)) > 0 then
sbe_index_set_bucket(index, "int", size, level_int)
end
if to_num(list_len(level_string)) > 0 then
sbe_index_set_bucket(index, "string", size, level_string)
end
if to_num(list_len(level_bool)) > 0 then
sbe_index_set_bucket(index, "bool", size, level_bool)
end
if to_num(list_len(level_list)) > 0 then
sbe_index_set_bucket(index, "list", size, level_list)
end
let evict_size = size - sbe_window_size()
if evict_size >= 2 then
sbe_evict_size(index, evict_size)
end
if pool_before_level > 0 then
let ratio = pool_count / pool_before_level
if ratio > 2.5 then
let high_growth_streak = high_growth_streak + 1
if high_growth_streak >= 2 then
let notes = list_push(notes, sbe_growth_note(size, ratio))
end
else
let high_growth_streak = 0
end
end
if found_match then
if alt_count > 0 then
let notes = list_push(notes, sbe_ambiguity_note(alt_count, size))
end
return ["OK", winner, notes]
end
let size = size + 1
end
let notes = list_push(notes, "reached max_size (" + max_size + ") without a match -- consider decomposing the target into smaller, independently-specified composites (see how after_space/take_before/take_after/splice were split out of replace_in_text) rather than raising max_size further")
return ["ERR", "no candidate up to size " + max_size, notes]
end
# ---- second mode: decision-list synthesis ----
#
# A finite literal-input -> literal-output mapping (e.g. "/health" ->
# "OK") isn't naturally reachable by expression composition alone -- this
# is a deliberately different, much simpler technique (build a chain of
# equality-guarded branches straight from the example pairs, ending in a
# default), not a variant of the enumerator above.
make a function called synthesize_lookup_from_examples takes input_name, examples, default_value returns ast
let node = ["Const", default_value]
let i = to_num(list_len(examples)) - 1
while i >= 0 do
let ex = examples[i]
let cond = ["Call", "str_eq", [["Input", input_name], ["Const", ex[0]]]]
let node = ["If", cond, ["Const", ex[1]], node]
let i = i - 1
end
return node
end
# ---- multi-language emission ----
#
# Walks a winning (non-decision-list) AST once, looking up each Call
# node's primitive/composite name in the registry's per-language snippet
# dict and substituting recursively-emitted argument code into the
# template's {0}/{1}/... placeholders. Errors BY NAME on a primitive with
# no snippet registered for the requested language -- matching
# self_hosting/lib/transpile_ruby.patlang's own convention of a clear
# ["Err", msg] over silently-broken output -- rather than guessing.
# Deliberately does not handle "If" nodes (decision-list ASTs use their
# own dedicated PatLang-only emitter below, since PatLang's `if` is a
# statement, not an expression -- there is no single-expression rendering
# to fall back to for that shape in this language).
make a function called sbe_quote_string takes s returns text
let out = sb_new()
sb_push(out, "\"")
let i = 0
let n = s.length
while i < n do
let c = char_code(s, i)
if c == 92 then
sb_push(out, "\\\\")
else
if c == 34 then
sb_push(out, "\\\"")
else
if c == 10 then
sb_push(out, "\\n")
else
if c == 13 then
sb_push(out, "\\r")
else
sb_push(out, s[i])
end
end
end
end
let i = i + 1
end
sb_push(out, "\"")
return sb_str(out)
end
make a function called sbe_emit_const takes v returns text
let ty = type_of(v)
if ty == "string" then
return sbe_quote_string(v)
end
if ty == "bool" then
if v then
return "true"
end
return "false"
end
return "" + v
end
make a function called sbe_replace_all takes s, needle, replacement returns out
let out = sb_new()
let i = 0
let nlen = needle.length
let slen = s.length
while i < slen do
if (nlen > 0) and (i <= slen - nlen) and (substr(s, i, nlen) == needle) then
sb_push(out, replacement)
let i = i + nlen
else
sb_push(out, s[i])
let i = i + 1
end
end
return sb_str(out)
end
make a function called sbe_fill_template takes tmpl, arg_texts returns out
let out = tmpl
let i = 0
let n = to_num(list_len(arg_texts))
while i < n do
let placeholder = "{" + i + "}"
let out = sbe_replace_all(out, placeholder, arg_texts[i])
let i = i + 1
end
return out
end
make a function called emit_ast takes node, lang, registry returns result
let tag = node[0]
if tag == "Const" then
return ["OK", sbe_emit_const(node[1])]
end
if tag == "Input" then
return ["OK", node[1]]
end
if tag == "Call" then
let prim = node[1]
let arg_nodes = node[2]
let tmpl = pr_snippet(registry, prim, lang)
if tmpl == "" then
return ["ERR", "no \"" + lang + "\" snippet registered for \"" + prim + "\""]
end
let arg_texts = []
let i = 0
let n = to_num(list_len(arg_nodes))
while i < n do
let sub = emit_ast(arg_nodes[i], lang, registry)
if sub[0] != "OK" then
return sub
end
let arg_texts = list_push(arg_texts, sub[1])
let i = i + 1
end
return ["OK", sbe_fill_template(tmpl, arg_texts)]
end
return ["ERR", "emit_ast: unsupported node tag \"" + tag + "\" for expression emission (decision-list ASTs use emit_decision_list_patlang)"]
end
# Full function-definition text for a plain expression-bodied composite
# (crlf/first_line/es_contains-shaped -- no branching), in PatLang.
make a function called emit_function_def_patlang takes name, param_names, node, registry returns result
let body = emit_ast(node, "patlang", registry)
if body[0] != "OK" then
return body
end
let params = sbe_join_comma(param_names)
let text = "make a function called " + name + " takes " + params + " returns result\n let result = " + body[1] + "\n return result\nend\n"
if to_num(list_len(param_names)) == 0 then
let text = "make a function called " + name + " returns result\n let result = " + body[1] + "\n return result\nend\n"
end
return ["OK", text]
end
make a function called sbe_join_comma takes items returns out
let out = sb_new()
let i = 0
let n = to_num(list_len(items))
while i < n do
if i > 0 then
sb_push(out, ", ")
end
sb_push(out, items[i])
let i = i + 1
end
return sb_str(out)
end
# Decision-list ASTs (synthesize_lookup_from_examples's output) are a
# strictly right-leaning chain of ["If", cond, then, rest] nodes ending in
# a default -- rendered directly as PatLang if/elif/.../else statements
# (CLAUDE.md's own convention for this repo: elif, never nested else-if),
# not through the generic expression emitter above.
make a function called emit_decision_list_patlang takes node, registry returns text
let out = sb_new()
let cur = node
let first = true
while cur[0] == "If" do
let cond_r = emit_ast(cur[1], "patlang", registry)
let then_r = emit_ast(cur[2], "patlang", registry)
if first then
sb_push(out, "if " + cond_r[1] + " then\n")
let first = false
else
sb_push(out, "elif " + cond_r[1] + " then\n")
end
sb_push(out, " return " + then_r[1] + "\n")
let cur = cur[3]
end
let default_r = emit_ast(cur, "patlang", registry)
sb_push(out, " else\n return " + default_r[1] + "\n end\n")
return sb_str(out)
end
make a function called emit_decision_function_patlang takes name, param_name, node, registry returns text
return "make a function called " + name + " takes " + param_name + " returns result\n " + emit_decision_list_patlang(node, registry) + "end\n"
end
# ---- composites become registry citizens ----
#
# Once synthesize_from_examples/synthesize_lookup_from_examples finds a
# winning AST, registering it back into the SAME registry under `name`
# means a LATER, larger search can call it as an ordinary primitive
# (arity = param count), and its call-site rendering is available in
# every language the registry already knows about -- call syntax
# `name(args...)` is uniform across PatLang/Ruby/Python, so no per-
# language body re-derivation is needed just to make the composite
# CALLABLE; only actually emitting its own definition (emit_function_def_
# patlang / emit_decision_function_patlang above) needs the AST itself,
# which register_composite stores alongside the call template.
make a function called register_composite takes registry, name, ast, param_names, arg_types, cost returns done
let snippets = pr_new_snippets()
let placeholders = []
let i = 0
let n = to_num(list_len(param_names))
while i < n do
let placeholders = list_push(placeholders, "{" + i + "}")
let i = i + 1
end
let call_text = name + "(" + sbe_join_comma(placeholders) + ")"
pr_set_snippet(snippets, "patlang", call_text)
pr_set_snippet(snippets, "ruby", call_text)
pr_set_snippet(snippets, "python", call_text)
# Composites are registered under ret_type "any" (rather than trying to
# infer a precise one here without access to the examples that proved
# them) and with no extra arg_contracts beyond their type tags -- this
# keeps register_composite's own signature unchanged for every existing
# caller. Being "any" only means pr_names_for_ret_type always offers a
# composite as a candidate for any requested type; it never causes one
# to be wrongly excluded, so this is a safe, low-precision default, not
# a correctness gap.
let arg_contracts = []
let i = 0
let n = to_num(list_len(arg_types))
while i < n do
let arg_contracts = list_push(arg_contracts, "")
let i = i + 1
end
send(registry, "set", name, ["composite", [ast, param_names], to_num(list_len(param_names)), cost, snippets, arg_types, "any", arg_contracts])
let idx = get(registry, "__by_ret_type__")
if not idx then
let idx = new("Dict", "pr_by_ret_type_" + pr_next_id())
send(registry, "set", "__by_ret_type__", idx)
end
let existing = get(idx, "any")
if existing then
send(idx, "set", "any", list_push(existing, name))
else
send(idx, "set", "any", [name])
end
return true
end
# Scans the index for a node whose value (under sample_bindings/
# example 0, the same value sbe_index_add already stored) exactly
# equals target_value, smallest size first -- so a witness-found match
# is never larger than one already sitting in the forward pool.
make a function called bidi_index_scan_by_value takes index, ty, target_value, max_size_so_far returns node
let s = 1
while s <= max_size_so_far do
let bucket = sbe_index_lookup(index, s, ty)
let i = 0
let n = to_num(list_len(bucket))
while i < n do
if bucket[i][3] == target_value then
return bucket[i][0]
end
let i = i + 1
end
let s = s + 1
end
return false
end
# concat(a, b) = target, split at position k: a = target[0:k], b =
# target[k:]. Looks up `a` FIRST (by its example-0 value), then -- only
# if found -- derives what `b` must be for EVERY example from that
# specific node's own per-example values (never assuming example 0's
# split point transfers literally to other examples, since target
# strings vary in length across examples), and looks up `b` the same
# way. Both sides must already exist in the forward index for this to
# fire -- Phase 1 doesn't hand back an open sub-goal for further
# recursive decomposition, it only reports an immediate meet.
make a function called bidi_try_concat_split takes examples, index, registry, max_size_so_far, k returns result
let t0 = examples[0][1]
let a0 = substr(t0, 0, k)
let node_a = bidi_index_scan_by_value(index, "string", a0, max_size_so_far)
if node_a then
let ok = true
let b_values = []
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let av = sbe_eval(node_a, ex[0], registry)
let ti = ex[1]
if av[0] == false then
let ok = false
else
let al = av[1].length
if (al > ti.length) or (substr(ti, 0, al) != av[1]) then
let ok = false
else
let b_values = list_push(b_values, substr(ti, al, ti.length - al))
end
end
let i = i + 1
end
if ok then
let node_b = bidi_index_scan_by_value(index, "string", b_values[0], max_size_so_far)
if node_b then
let bok = true
let j = 0
let jn = to_num(list_len(examples))
while j < jn do
let bv = sbe_eval(node_b, examples[j][0], registry)
if (bv[0] == false) or (bv[1] != b_values[j]) then
let bok = false
end
let j = j + 1
end
if bok then
return ["OK", ["Call", "concat", [node_a, node_b]]]
end
end
end
end
return ["ERR"]
end
make a function called bidi_try_concat takes examples, index, registry, max_size_so_far returns result
let kn = examples[0][1].length
let k = 0
while k <= kn do
let r = bidi_try_concat_split(examples, index, registry, max_size_so_far, k)
if r[0] == "OK" then
return r
end
let k = k + 1
end
return ["ERR"]
end
# add(v, other) = target => other = target - v, and sub(v, other) =
# target => other = v - target -- both checked against the SAME scan
# over already-indexed int candidates for `v`, since both directions
# are worth trying per candidate at negligible extra cost.
make a function called bidi_try_arith takes examples, index, registry, max_size_so_far returns result
let s = 1
while s <= max_size_so_far do
let bucket = sbe_index_lookup(index, s, "int")
let bi = 0
let bn = to_num(list_len(bucket))
while bi < bn do
let node_v = bucket[bi][0]
let n = to_num(list_len(examples))
let ok_add = true
let other_add = []
let i = 0
while i < n do
let ex = examples[i]
let vv = sbe_eval(node_v, ex[0], registry)
if vv[0] == false then
let ok_add = false
else
let other_add = list_push(other_add, ex[1] - vv[1])
end
let i = i + 1
end
if ok_add then
let node_other = bidi_index_scan_by_value(index, "int", other_add[0], max_size_so_far)
if node_other then
let verify_ok = true
let j = 0
while j < n do
let ov = sbe_eval(node_other, examples[j][0], registry)
if (ov[0] == false) or (ov[1] != other_add[j]) then
let verify_ok = false
end
let j = j + 1
end
if verify_ok then
return ["OK", ["Call", "add", [node_v, node_other]]]
end
end
end
let ok_sub = true
let other_sub = []
let i2 = 0
while i2 < n do
let ex = examples[i2]
let vv = sbe_eval(node_v, ex[0], registry)
if vv[0] == false then
let ok_sub = false
else
let other_sub = list_push(other_sub, vv[1] - ex[1])
end
let i2 = i2 + 1
end
if ok_sub then
let node_other2 = bidi_index_scan_by_value(index, "int", other_sub[0], max_size_so_far)
if node_other2 then
let verify_ok2 = true
let j2 = 0
while j2 < n do
let ov2 = sbe_eval(node_other2, examples[j2][0], registry)
if (ov2[0] == false) or (ov2[1] != other_sub[j2]) then
let verify_ok2 = false
end
let j2 = j2 + 1
end
if verify_ok2 then
return ["OK", ["Call", "sub", [node_v, node_other2]]]
end
end
end
let bi = bi + 1
end
let s = s + 1
end
return ["ERR"]
end
# ---- Phase 3: range witnesses for gt/geq/eq_int ----
#
# A boolean target from a comparison doesn't pin its two arguments to
# single values the way concat's split or add/sub's two-sum inversion
# do -- gt(a,b)=true only pins the RELATION between a and b, and the
# set of (a,b) pairs satisfying a relation is unbounded in general (any
# a>b at all). The useful, bounded move: scan pairs of ALREADY forward-
# built int candidates directly (not inventing new ones) and check
# whether the relation already holds across every example -- a
# filtering pass over existing work, exactly like concat/arith's
# witnesses, just checking a relation instead of deriving one exact
# target value per side. Smallest-total-size-first (outer loop by size)
# so a match here is never larger than one plain forward search over
# gt/geq/eq_int at the same level would eventually find -- this witness
# doesn't skip ahead of when the forward loop would naturally construct
# the same expression (their combined size is fixed either way), it
# just reaches it via a cheaper existing-pool scan instead of sbe_
# build_calls's own combinatorial arg-type-and-contract generation.
make a function called bidi_relation_holds takes rel, av, bv returns yes
if rel == "gt" then
return av > bv
end
if rel == "geq" then
return av >= bv
end
if rel == "eq_int" then
return av == bv
end
return false
end
make a function called bidi_try_range takes examples, index, registry, max_size_so_far, primitive_names returns result
let rels = []
if bidi_list_contains(primitive_names, "gt") then
let rels = list_push(rels, "gt")
end
if bidi_list_contains(primitive_names, "geq") then
let rels = list_push(rels, "geq")
end
if bidi_list_contains(primitive_names, "eq_int") then
let rels = list_push(rels, "eq_int")
end
if to_num(list_len(rels)) == 0 then
return ["ERR"]
end
let sa = 1
while sa <= max_size_so_far do
let bucket_a = sbe_index_lookup(index, sa, "int")
let ai = 0
let an = to_num(list_len(bucket_a))
while ai < an do
let node_a = bucket_a[ai][0]
let sb = 1
while sb <= max_size_so_far do
let bucket_b = sbe_index_lookup(index, sb, "int")
let bi = 0
let bn = to_num(list_len(bucket_b))
while bi < bn do
let node_b = bucket_b[bi][0]
let ri = 0
let rn = to_num(list_len(rels))
while ri < rn do
let rel = rels[ri]
let ok = true
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let av = sbe_eval(node_a, ex[0], registry)
let bv = sbe_eval(node_b, ex[0], registry)
if (av[0] == false) or (bv[0] == false) then
let ok = false
else
if bidi_relation_holds(rel, av[1], bv[1]) != ex[1] then
let ok = false
end
end
let i = i + 1
end
if ok then
return ["OK", ["Call", rel, [node_a, node_b]]]
end
let ri = ri + 1
end
let bi = bi + 1
end
let sb = sb + 1
end
let ai = ai + 1
end
let sa = sa + 1
end
return ["ERR"]
end
# ---- cond as a direct scan witness, not partition-and-recurse ----
#
# The original bidi_try_cond commits to a COMPLETE partition of the
# examples upfront, then runs THREE full recursive syntheses (a, b,
# test) before ever checking whether the combination holds together --
# most of the 2^n-2 candidate partitions are wrong, but they don't fail
# fast: they succeed locally on their own subset and waste a full
# expensive sub-search before the outer verification catches it.
# Measured directly on the real 8-example case: 55s average per
# recursive sub-search, with no fast-fail path for a bad guess.
#
# This is the constraint-propagation alternative: `test`/`a`/`b` are
# never separately synthesized at all -- they're read directly off the
# SAME shared, already-being-built forward index every OTHER witness in
# this file already scans (bidi_try_concat/arith/range), and checked
# for per-example consistency using their ALREADY-CACHED behavior
# (sbe_eval against each example's own bindings -- a plain value
# lookup, not a new synthesis). A bad (test,a,b) triple is rejected in
# O(examples) cheap comparisons, not after a full recursive solve. The
# "local world state" is exactly this: per-example, what value has this
# specific candidate ALREADY produced -- never a combinatorial subset
# of facts (that's the STRIPS/GOAP shape issue #71 already ruled out
# for this problem), just one cached value per example per candidate.
#
# Tried directly, not just reasoned about: the constraint-propagation
# fix is real (validated on a small ambiguous case -- correct minimal
# answer, ~700ms, matching Phase 3's own result). But wiring it into
# bidi_witness_pass (tried every level, like concat/arith/range) made
# the real first_exceeding case WORSE than the partition-based
# bidi_try_cond, not better: this scan is a TRIPLE-nested loop over
# (a,b,test) candidate pools -- cubic in pool size -- and this domain's
# `any`-typed pools are already large (the same combinatorial driver
# behind issue #73/#69). It genuinely exhausted the interpreter's 8GB
# memory cap at size 8 alone on the 5-example case, where partition-
# based cond finds the answer in ~29s total. Kept here as a documented,
# available alternative (NOT wired into bidi_witness_pass's default
# flow) -- a real, different tool for a domain with small-to-modest
# per-level pools, not a strict improvement for one with large ones. A
# genuinely better version would need value-INDEXED lookups for the
# third argument (given test+a, look up the exact node matching the
# remaining examples' required values directly, the same trick concat/
# arith's witnesses already use) instead of a brute nested scan over
# every candidate -- real further engineering, not attempted here.
make a function called bidi_try_cond_scan takes examples, index, registry, max_size_so_far, target_type returns result
let sa = 1
while sa <= max_size_so_far do
let bucket_a = sbe_index_lookup(index, sa, target_type)
let ai = 0
let an = to_num(list_len(bucket_a))
while ai < an do
let node_a = bucket_a[ai][0]
let sb = 1
while sb <= max_size_so_far do
let bucket_b = sbe_index_lookup(index, sb, target_type)
let bi = 0
let bn = to_num(list_len(bucket_b))
while bi < bn do
let node_b = bucket_b[bi][0]
if node_a != node_b then
let st = 1
while st <= max_size_so_far do
let bucket_t = sbe_index_lookup(index, st, "bool")
let ti = 0
let tn = to_num(list_len(bucket_t))
while ti < tn do
let node_t = bucket_t[ti][0]
let ok = true
let i = 0
let n = to_num(list_len(examples))
while i < n do
let ex = examples[i]
let tv = sbe_eval(node_t, ex[0], registry)
if tv[0] == false then
let ok = false
else
let chosen = node_a
if tv[1] == false then
let chosen = node_b
end
let cv = sbe_eval(chosen, ex[0], registry)
if (cv[0] == false) or (cv[1] != ex[1]) then
let ok = false
end
end
let i = i + 1
end
if ok then
return ["OK", ["Call", "cond", [node_t, node_a, node_b]]]
end
let ti = ti + 1
end
let st = st + 1
end
end
let bi = bi + 1
end
let sb = sb + 1
end
let ai = ai + 1
end
let sa = sa + 1
end
return ["ERR"]
end
make a function called bidi_witness_pass takes examples, index, registry, max_size_so_far, target_type, primitive_names returns result
if bidi_list_contains(primitive_names, "cond") then
let cr = bidi_try_cond_combined(examples, index, registry, max_size_so_far, target_type)
if cr[0] == "OK" then
return cr
end
end
if target_type == "string" then
return bidi_try_concat(examples, index, registry, max_size_so_far)
end
if target_type == "int" then
return bidi_try_arith(examples, index, registry, max_size_so_far)
end
if target_type == "bool" then
return bidi_try_range(examples, index, registry, max_size_so_far, primitive_names)
end
return ["ERR"]
end
# ---- Phase 2: cond's disjunctive witness ----
#
# cond(test, a, b) = target doesn't have ONE inverse the way concat/add
# do -- it has two, and they don't compose the same way (a split always
# names exactly one pair of sub-goals; a branch could be either of two
# DIFFERENT sub-expressions, and which examples belong to which branch
# isn't known in advance). The witness here: try every way of
# partitioning the examples into two non-empty groups, and for each
# partition, search independently for (a) an expression correct on the
# "true" group, (b) an expression correct on the "false" group, and
# (c) a boolean expression that is true on the "true" group and false
# on the "false" group -- reusing the SAME recursive search (forward +
# Phase 1 witnesses) for all three, not a separate mechanism. Only
# succeeds if all three sub-searches succeed AND the assembled
# cond(test,a,b) verifies against every original example (a partition
# guess can be internally consistent per-branch yet still wrong overall
# if the "test" that separates them doesn't generalize the same way the
# real domain does -- sbe_matches_all is the final, unconditional
# check, same as everywhere else in this codebase).
#
# Bounded by 2^n - 2 partitions for n examples (every non-empty,
# non-full split; no attempt to dedupe a partition against its A/B-
# swapped mirror, which just tries the same work twice, not more of it)
# -- fine for the single-digit example counts this codebase's own
# demos use, not attempted for large n. depth caps recursion (each
# sub-search can itself try to build a cond via its own boolean-test
# search), since a boolean sub-search could otherwise try to explain
# itself with another cond, recursively, without limit.
make a function called bidi_all_partitions takes n returns partitions
let out = [[]]
let i = 0
while i < n do
let next = []
let j = 0
let jn = to_num(list_len(out))
while j < jn do
let p = out[j]
let next = list_push(next, list_push(p, true))
let next = list_push(next, list_push(p, false))
let j = j + 1
end
let out = next
let i = i + 1
end
let filtered = []
let k = 0
let kn = to_num(list_len(out))
while k < kn do
let p = out[k]
let all_true = true
let all_false = true
let m = 0
let mn = to_num(list_len(p))
while m < mn do
if p[m] then
let all_false = false
else
let all_true = false
end
let m = m + 1
end
if (not all_true) and (not all_false) then
let filtered = list_push(filtered, p)
end
let k = k + 1
end
return filtered
end
make a function called bidi_subset_examples takes examples, partition, want returns subset
let out = []
let i = 0
let n = to_num(list_len(examples))
while i < n do
if partition[i] == want then
let out = list_push(out, examples[i])
end
let i = i + 1
end
return out
end
make a function called bidi_bool_examples takes examples, partition returns bool_examples
let out = []
let i = 0
let n = to_num(list_len(examples))
while i < n do
let out = list_push(out, [examples[i][0], partition[i]])
let i = i + 1
end
return out
end
# The boolean TEST search is over the FULL original example count
# (bidi_bool_examples relabels every example, it never subsets), so
# leaving "cond" available to it means a genuinely redundant recursion:
# searching for a predicate by trying to build ANOTHER disjunctive cond
# (itself needing its own predicate search, its own two branches...)
# at full "any"-type combinatorial cost, when what's actually needed is
# just a plain comparison. Confirmed directly to be the dominant cost,
# not a memory-hygiene issue: 574 candidates for a single nested `cond`
# attempt at size 6 alone, at the FULL 5-example count, one of 92
# equally-expensive recursive calls that together exhausted the
# interpreter's memory cap. Excluding "cond" from the test search's own
# primitive list removes this specific redundant recursion outright --
# a nested-cond-as-test is a real, rarer capability this doesn't
# attempt to preserve, not assumed harmless to drop.
make a function called bidi_strip_cond takes primitive_names returns filtered
let out = []
let i = 0
let n = to_num(list_len(primitive_names))
while i < n do
if primitive_names[i] != "cond" then
let out = list_push(out, primitive_names[i])
end
let i = i + 1
end
return out
end
make a function called bidi_list_contains takes items, value returns yes
let i = 0
let n = to_num(list_len(items))
while i < n do
if items[i] == value then
return true
end
let i = i + 1
end
return false
end
# Every concrete type reachable from `available_types` within `cap`
# primitive calls, ignoring whether a primitive's OTHER argument
# positions are actually cheap to fill (the standard "delete-relaxation"
# move: relaxing a constraint can only ever make the true cost look
# smaller than it really is, never larger, which is exactly what
# admissibility needs -- see plan-file note on this technique). One
# registered primitive with ANY argument position matching an already-
# reachable type makes its OWN return type reachable one hop further
# out; "any"-typed argument positions are trivially satisfiable by
# construction. Returns a Dict from type name -> hop count (0 for
# types already in `available_types`).
make a function called bidi_type_reachability takes available_types, registry, primitive_names, cap returns reach
let reach = new("Dict", "bidi_reach_" + pr_next_id())
let ai = 0
let an = to_num(list_len(available_types))
while ai < an do
send(reach, "set", available_types[ai], 0)
let ai = ai + 1
end
let dist = 0
while dist < cap do
let dist = dist + 1
let added_any = false
let p = 0
let pn = to_num(list_len(primitive_names))
while p < pn do
let entry = pr_lookup(registry, primitive_names[p])
if entry then
let ret_type = entry[6]
if not get(reach, ret_type) then
let arg_types = entry[5]
let reachable_arg = false
let a = 0
let an2 = to_num(list_len(arg_types))
while a < an2 do
let at = arg_types[a]
if (at == "any") or get(reach, at) then
let reachable_arg = true
end
let a = a + 1
end
if reachable_arg then
send(reach, "set", ret_type, dist)
let added_any = true
end
end
end
let p = p + 1
end
if not added_any then
let dist = cap
end
end
return reach
end
make a function called bidi_available_types takes examples, input_names, extra_consts returns types
let out = ["int"]
let bindings = examples[0][0]
let i = 0
let n = to_num(list_len(input_names))
while i < n do
let ty = type_of(get(bindings, input_names[i]))
if not bidi_list_contains(out, ty) then
let out = list_push(out, ty)
end
let i = i + 1
end
let j = 0
let jn = to_num(list_len(extra_consts))
while j < jn do
let ty = type_of(extra_consts[j])
if not bidi_list_contains(out, ty) then
let out = list_push(out, ty)
end
let j = j + 1
end
return out
end
# Admissible lower bound on the size of ANY expression matching every
# example in this branch, computable WITHOUT running the real search:
# if a single input (or a single literal constant) already equals the
# target for every example in the branch, 1 is not just a bound, it's
# the exact achievable minimum (a bare leaf). Otherwise, use the type-
# reachability graph: if the target's own type is already available
# (just not at the right VALUE), one "maintaining" primitive call
# suffices at minimum -- cost 2 (a Call plus at least one leaf arg). If
# the target's type needs `h` primitive hops to reach from the
# available types, a chain of `h` necessarily-required Call nodes has
# size at least `h` (each contributes >= 1) plus at least one more leaf
# somewhere -- `h + 1`, a safe (if loose) floor, never overestimating
# since it's derived from an already-relaxed (optimistic) reachability
# search. Falls back to the OLD flat floor of 2 only if reachability
# search doesn't find the type within `cap` hops (a real "no idea, but
# it's definitely more than a leaf" case, not a silent wrong answer --
# admissible either way, just less informative).
make a function called bidi_branch_lower_bound takes examples, input_names, extra_consts, registry, primitive_names returns bound
let n = to_num(list_len(examples))
let ii = 0
let in_n = to_num(list_len(input_names))
while ii < in_n do
let name = input_names[ii]
let matches = true
let i = 0
while i < n do
let ex = examples[i]
if get(ex[0], name) != ex[1] then
let matches = false
end
let i = i + 1
end
if matches then
return 1
end
let ii = ii + 1
end
let const_matches = true
let j = 0
while j < n do
if examples[j][1] != examples[0][1] then
let const_matches = false
end
let j = j + 1
end
if const_matches then
return 1
end
let target_type = type_of(examples[0][1])
let available_types = bidi_available_types(examples, input_names, extra_consts)
if bidi_list_contains(available_types, target_type) then
return 2
end
let cap = 4
let reach = bidi_type_reachability(available_types, registry, primitive_names, cap)
let hops = get(reach, target_type)
if hops then
return hops + 1
end
return 2
end
# A*-style: rank every candidate partition by an admissible lower bound
# on the total cost cond(test,a,b) could possibly achieve (h(test)=3,
# the cheapest a real non-degenerate comparison could ever be, plus
# each branch's own bidi_branch_lower_bound, plus 1 for the cond call
# itself), explore in ascending order, and stop the instant the best
# VERIFIED result found so far is already <= the next unexplored
# partition's lower bound -- nothing left could possibly beat it. This
# is what actually fixes a real, observed bug, not just a speed
# optimization: naive first-found-wins order let an arbitrarily large,
# numerically-coincidental cond tree get accepted before a genuinely
# smaller (and so more likely to actually generalize, same reasoning
# the plain forward enumerator's own smallest-first order relies on)
# one was ever considered -- confirmed directly: a first version
# returned a 4-deep nested cond/add tree that verified against all 5
# training examples but failed BOTH of two held-out checks. Ordering by
# a real lower bound and keeping only the smallest verified result
# restores the same "prefer minimal, more general solutions" property
# the rest of this codebase already depends on -- it does not, and
# cannot, eliminate overfitting in principle (a genuinely small AST can
# still fail to generalize; the existing "add a disambiguating example"
# remedy applies here exactly as it does everywhere else in this file).
# ---- cond: partition enumeration + shared-index scan, combined ----
#
# Keeps the partition-based approach's cheap structure (enumerate
# candidate splits, bound to 2^n-2 rather than a full cross product) but
# replaces its costliest step -- a full RECURSIVE re-synthesis of a, b,
# and test from scratch per partition -- with a single-pass scan of the
# SAME shared, already-growing forward index every other witness in
# this file reads from, checking per-example consistency against
# already-cached candidate values (the scan-based witness's real
# insight) instead of spawning new searches. Per partition this is
# O(pool size) for each of a/b/test, not the O(pool size^3) triple-
# nested cross product a bare scan needs when it isn't first narrowed
# by a partition -- the combination is what makes both halves cheap
# where each was expensive alone.
make a function called bidi_scan_for_subset_match takes index, ty, sub_examples, max_size_so_far, registry returns node
let s = 1
while s <= max_size_so_far do
let bucket = sbe_index_lookup(index, s, ty)
let i = 0
let n = to_num(list_len(bucket))
while i < n do
let candidate = bucket[i][0]
let ok = true
let j = 0
let jn = to_num(list_len(sub_examples))
while j < jn do
let ex = sub_examples[j]
let v = sbe_eval(candidate, ex[0], registry)
if (v[0] == false) or (v[1] != ex[1]) then
let ok = false
end
let j = j + 1
end
if ok then
return candidate
end
let i = i + 1
end
let s = s + 1
end
return false
end
# Optional structural contract on the assembled candidate, e.g. "must
# not directly compare two named inputs" -- set via set_var("bidi_
# contract_fn", "fn_name") before calling bidi_synthesize_from_examples,
# cleared (set_var("bidi_contract_fn", false)) afterward. Purely
# additive: unset (false/missing) behaves exactly as before, so every
# existing caller (all committed demos) is unaffected. Checked here
# rather than threaded as a parameter through bidi_witness_pass/bidi_
# synthesize_from_examples's whole call graph, to avoid touching those
# signatures (and every existing call site) for what is, so far, a
# single targeted use.
make a function called bidi_contract_ok takes node returns ok
let contract_fn_name = get("__vars", "bidi_contract_fn")
if not contract_fn_name then
return true
end
return apply(contract_fn_name, node)
end
make a function called bidi_try_cond_combined takes examples, index, registry, max_size_so_far, target_type returns result
let n = to_num(list_len(examples))
if n < 2 then
return ["ERR"]
end
let partitions = bidi_all_partitions(n)
let best_size = -1
let best_candidate = false
let alt_count = 0
let pi = 0
let pn = to_num(list_len(partitions))
while pi < pn do
let partition = partitions[pi]
let sub_true = bidi_subset_examples(examples, partition, true)
let sub_false = bidi_subset_examples(examples, partition, false)
let node_a = bidi_scan_for_subset_match(index, target_type, sub_true, max_size_so_far, registry)
if node_a then
let node_b = bidi_scan_for_subset_match(index, target_type, sub_false, max_size_so_far, registry)
if node_b then
let bool_examples = bidi_bool_examples(examples, partition)
let node_t = bidi_scan_for_subset_match(index, "bool", bool_examples, max_size_so_far, registry)
if node_t then
let candidate = ["Call", "cond", [node_t, node_a, node_b]]
if sbe_matches_all(candidate, examples, registry) and bidi_contract_ok(candidate) then
let actual_size = sbe_size(candidate)
if (best_size < 0) or (actual_size < best_size) then
let best_size = actual_size
let best_candidate = candidate
let alt_count = 0
else
if actual_size == best_size then
let alt_count = alt_count + 1
end
end
end
end
end
end
let pi = pi + 1
end
if best_candidate then
return ["OK", best_candidate, alt_count, best_size]
end
return ["ERR"]
end
make a function called bidi_try_cond takes examples, input_names, extra_consts, registry, primitive_names, max_size, depth returns result
let n = to_num(list_len(examples))
if (n < 2) or (depth > 2) then
return ["ERR"]
end
let partitions = bidi_all_partitions(n)
let scored = []
let pi = 0
let pn = to_num(list_len(partitions))
while pi < pn do
let partition = partitions[pi]
let sub_true = bidi_subset_examples(examples, partition, true)
let sub_false = bidi_subset_examples(examples, partition, false)
let h = 1 + 3 + bidi_branch_lower_bound(sub_true, input_names, extra_consts, registry, primitive_names) + bidi_branch_lower_bound(sub_false, input_names, extra_consts, registry, primitive_names)
let scored = list_push(scored, [h, partition, sub_true, sub_false])
let pi = pi + 1
end
let scored = bidi_sort_by_heuristic(scored)
# Stops on strictly-worse lower bound only (h > best_size), NOT on
# h == best_size -- a tying heuristic can still produce a candidate
# that TIES on actual size, and those ties are exactly the signal
# worth keeping: multiple structurally different partitions verifying
# at the same minimal size is the same "the examples under-specify
# this" ambiguity sbe_ambiguity_note already surfaces for the plain
# enumerator (self_hosting/lib/synthesis_by_example.patlang). A first
# version of this search stopped at the very first verified candidate
# regardless of size and returned a confidently WRONG, deeply nested
# answer on a known-under-specified 5-example case -- it never even
# LOOKED for a second explanation, so there was no chance to notice
# the ambiguity that was actually there. Tracking alt_count here is
# the fix for that blind spot, not just a nicety.
let best_size = -1
let best_candidate = false
let alt_count = 0
let si = 0
let sn = to_num(list_len(scored))
while si < sn do
let entry = scored[si]
let h = entry[0]
if (best_size >= 0) and (h > best_size) then
let si = sn
else
let partition = entry[1]
let sub_true = entry[2]
let sub_false = entry[3]
let a_result = bidi_synthesize_from_examples_d(sub_true, input_names, extra_consts, registry, primitive_names, max_size, depth)
if a_result[0] == "OK" then
let b_result = bidi_synthesize_from_examples_d(sub_false, input_names, extra_consts, registry, primitive_names, max_size, depth)
if b_result[0] == "OK" then
let bool_examples = bidi_bool_examples(examples, partition)
let t_result = bidi_synthesize_from_examples_d(bool_examples, input_names, extra_consts, registry, bidi_strip_cond(primitive_names), max_size, depth)
if t_result[0] == "OK" then
let candidate = ["Call", "cond", [t_result[1], a_result[1], b_result[1]]]
if sbe_matches_all(candidate, examples, registry) then
let actual_size = sbe_size(candidate)
if (best_size < 0) or (actual_size < best_size) then
let best_size = actual_size
let best_candidate = candidate
let alt_count = 0
else
if actual_size == best_size then
let alt_count = alt_count + 1
end
end
end
end
end
end
let si = si + 1
end
end
if best_candidate then
return ["OK", best_candidate, alt_count, best_size]
end
return ["ERR"]
end
# Plain insertion sort by entry[0] (the heuristic) -- partition counts
# here are small (2^n - 2 for this codebase's own single-digit example
# counts), so O(n^2) is the right tradeoff against writing/maintaining
# a real sort for a list this size.
make a function called bidi_sort_by_heuristic takes scored returns sorted
let out = []
let i = 0
let n = to_num(list_len(scored))
while i < n do
let item = scored[i]
let inserted = false
let j = 0
let out2 = []
let jn = to_num(list_len(out))
while j < jn do
if (not inserted) and (item[0] < out[j][0]) then
let out2 = list_push(out2, item)
let inserted = true
end
let out2 = list_push(out2, out[j])
let j = j + 1
end
if not inserted then
let out2 = list_push(out2, item)
end
let out = out2
let i = i + 1
end
return out
end
# Public entry point -- unchanged signature, depth always starts at 0.
make a function called bidi_synthesize_from_examples takes examples, input_names, extra_consts, registry, primitive_names, max_size returns result
return bidi_synthesize_from_examples_d(examples, input_names, extra_consts, registry, primitive_names, max_size, 0)
end
# Frees its own scratch Dicts (`index`/`seen`) on every exit path,
# regardless of which return in the impl function below actually fired
# -- PatLang's object store (OBJECTS, rust-runtime/src/ir/hosts.rs)
# never frees an entry on its own, and this function is called
# recursively, often many times over, by bidi_try_cond's partition
# search (confirmed directly: 92 recursive sub-searches on a real case,
# none individually large, exhausted the interpreter's own memory cap
# purely from the accumulated, never-freed count). Delegating the real
# work to `_impl` (which takes index/seen as plain parameters instead
# of creating them itself) is what makes a single cleanup point here
# possible without duplicating it across every one of `_impl`'s own
# early returns.
make a function called bidi_synthesize_from_examples_d takes examples, input_names, extra_consts, registry, primitive_names, max_size, depth returns result
let index = sbe_index_new()
let seen = new("Dict", "bidi_seen_" + pr_next_id())
let result = bidi_synthesize_from_examples_impl(examples, input_names, extra_consts, registry, primitive_names, max_size, depth, index, seen)
return result
end
# Same overall shape as synthesize_from_examples (same leaf-seeding,
# same forward per-level growth via sbe_build_calls/sbe_evaluate_
# candidates, same windowing) -- the additions are bidi_witness_pass
# (concat/add/sub, Phase 1), tried once per level, and bidi_try_cond
# (Phase 2), tried once up front (it doesn't depend on the forward
# index at all, unlike Phase 1's witnesses, so there's nothing to gain
# from retrying it as the index grows).
make a function called bidi_synthesize_from_examples_impl takes examples, input_names, extra_consts, registry, primitive_names, max_size, depth, index, seen returns result
let consts = sbe_list_concat(sbe_default_int_consts(), extra_consts)
let sample_bindings = examples[0][0]
let leaves = sbe_seed_leaves(input_names, consts)
let notes = []
let target_type = type_of(examples[0][1])
let winner = ["Const", ""]
let found_match = false
let i = 0
let n = to_num(list_len(leaves))
while i < n do
let node = leaves[i]
if sbe_matches_all(node, examples, registry) then
if not found_match then
let found_match = true
let winner = node
end
end
let key = sbe_output_key(node, examples, registry)
if not get(seen, key) then
send(seen, "set", key, true)
sbe_index_add(index, sbe_wrap(node, registry, sample_bindings))
end
let i = i + 1
end
if found_match then
return ["OK", winner, notes]
end
let wr = bidi_witness_pass(examples, index, registry, 1, target_type, primitive_names)
if wr[0] == "OK" then
if sbe_matches_all(wr[1], examples, registry) then
if (to_num(list_len(wr)) > 2) and (wr[2] > 0) then
let notes = list_push(notes, sbe_ambiguity_note(wr[2], wr[3]))
end
return ["OK", wr[1], notes]
end
end
let size = 2
while size <= max_size do
print("bidi_synthesize_from_examples: size=" + size + " at " + now_ms())
let level_int = []
let level_string = []
let level_bool = []
let level_list = []
let winner = ["Const", ""]
let found_match = false
let p = 0
let pn = to_num(list_len(primitive_names))
while p < pn do
let prim = primitive_names[p]
let entry = pr_lookup(registry, prim)
if entry then
let arg_types = entry[5]
let arg_contracts = entry[7]
let prim_cost = to_num(entry[3])
let candidates = sbe_build_calls(prim, arg_types, arg_contracts, size, index, prim_cost)
let cn = to_num(list_len(candidates))
let results = sbe_evaluate_candidates(candidates, examples, registry, sample_bindings)
let c = 0
while c < cn do
let node = candidates[c]
let r = results[c]
let ok = r[0]
let key = r[1]
let ty = r[2]
let value = r[3]
if ok then
if not found_match then
let found_match = true
let winner = node
end
end
if not get(seen, key) then
send(seen, "set", key, true)
let typed = [node, size, ty, value]
if ty == "int" then
let level_int = list_push(level_int, typed)
else
if ty == "string" then
let level_string = list_push(level_string, typed)
else
if ty == "bool" then
let level_bool = list_push(level_bool, typed)
else
if ty == "list" then
let level_list = list_push(level_list, typed)
end
end
end
end
end
let c = c + 1
end
end
let p = p + 1
end
if to_num(list_len(level_int)) > 0 then
sbe_index_set_bucket(index, "int", size, level_int)
end
if to_num(list_len(level_string)) > 0 then
sbe_index_set_bucket(index, "string", size, level_string)
end
if to_num(list_len(level_bool)) > 0 then
sbe_index_set_bucket(index, "bool", size, level_bool)
end
if to_num(list_len(level_list)) > 0 then
sbe_index_set_bucket(index, "list", size, level_list)
end
let evict_size = size - sbe_window_size()
if evict_size >= 2 then
sbe_evict_size(index, evict_size)
end
if found_match then
return ["OK", winner, notes]
end
let wr2 = bidi_witness_pass(examples, index, registry, size, target_type, primitive_names)
if wr2[0] == "OK" then
if sbe_matches_all(wr2[1], examples, registry) then
if (to_num(list_len(wr2)) > 2) and (wr2[2] > 0) then
let notes = list_push(notes, sbe_ambiguity_note(wr2[2], wr2[3]))
end
return ["OK", wr2[1], notes]
end
end
let size = size + 1
end
let notes = list_push(notes, "reached max_size (" + max_size + ") without a match")
return ["ERR", "no candidate up to size " + max_size, notes]
end
# =============================================================================
# Test framework (Stage 1 dialect): unit assertions plus a Gherkin-style
# feature runner. Step definitions are registered in the object store keyed
# by their text; features are plain text dispatched line by line, so the
# same framework covers unit, integration, and behaviour tests.
# =============================================================================
make a function called t_init returns done
set_var("t_pass", 0)
set_var("t_fail", 0)
set_var("t_tagfilter", "")
set_var("t_pending_tags", "")
set_var("t_skipping", 0)
return true
end
make a function called contains_text takes hay, needle returns r
if needle.length > hay.length then
return false
end
let i = 0
while i <= hay.length - needle.length do
if substr(hay, i, needle.length) == needle then
return true
end
let i = i + 1
end
return false
end
make a function called check takes label, actual, expected returns ok
if actual == expected then
set_var("t_pass", get("__vars", "t_pass") + 1)
print(" ok: " + label)
return true
else
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: " + label + " (got " + actual + ", want " + expected + ")")
return false
end
end
make a function called t_report returns ok
let p = get("__vars", "t_pass")
let f = get("__vars", "t_fail")
print("tests: " + p + " passed, " + f + " failed")
if f == 0 then
print("ALL TESTS PASSED")
return true
else
print("TESTS FAILED")
return false
end
end
# ---- Gherkin runner ----
# Register a step: step("a fresh till", "st_fresh_till")
make a function called step takes text, fname returns done
new("Step", text)
send(text, "set", "fn", fname)
return true
end
make a function called starts_with takes s, prefix returns r
if s.length < prefix.length then
return false
end
return substr(s, 0, prefix.length) == prefix
end
make a function called trim_left takes s returns out
let i = 0
let scanning = true
while (i < s.length) and scanning do
let c = char_code(s, i)
if (c == 32) or (c == 9) then
let i = i + 1
else
let scanning = false
end
end
return substr(s, i, s.length - i)
end
# Strip a Gherkin keyword; returns the step text or "" if not a step line
make a function called step_text takes line returns out
if starts_with(line, "Given ") then
return substr(line, 6, line.length - 6)
end
if starts_with(line, "When ") then
return substr(line, 5, line.length - 5)
end
if starts_with(line, "Then ") then
return substr(line, 5, line.length - 5)
end
if starts_with(line, "And ") then
return substr(line, 4, line.length - 4)
end
return ""
end
# Run only scenarios whose preceding @tag line contains `tag` ("" = all)
make a function called run_feature_tagged takes feature, tag returns ok
set_var("t_tagfilter", tag)
return run_feature(feature)
end
make a function called run_feature_file takes path returns ok
return run_feature(read_file(path))
end
make a function called run_feature takes feature returns ok
let h = str_intern(feature)
let n = sc_len(h)
let i = 0
let line = sb_new()
while i <= n do
let c = sc_code(h, i)
if (c == 10) or (c == -1) then
let raw = trim_left(sb_str(line))
let line = sb_new()
if starts_with(raw, "@") then
set_var("t_pending_tags", raw)
end
if starts_with(raw, "Feature:") then
print(raw)
end
if starts_with(raw, "Scenario:") then
let filter = get("__vars", "t_tagfilter")
let tags = get("__vars", "t_pending_tags")
set_var("t_pending_tags", "")
if filter then
if tags then
if contains_text(tags, filter) then
set_var("t_skipping", 0)
print(raw + " [" + tags + "]")
else
set_var("t_skipping", 1)
print(raw + " [skipped: needs " + filter + "]")
end
else
set_var("t_skipping", 1)
print(raw + " [skipped: needs " + filter + "]")
end
else
set_var("t_skipping", 0)
print(raw)
end
else
let text = step_text(raw)
if (text != "") and (get("__vars", "t_skipping") != 1) then
if starts_with(text, "require ") then
handle_contract_step("require", substr(text, 8, text.length - 8))
else
if starts_with(text, "ensure ") then
handle_contract_step("ensure", substr(text, 7, text.length - 7))
else
let fname = get(text, "fn")
if fname then
apply(fname)
else
set_var("t_fail", get("__vars", "t_fail") + 1)
print(" FAIL: undefined step: " + text)
end
end
end
end
end
let i = i + 1
else
if c == 13 then
let i = i + 1
else
sb_push(line, sc_char(h, i))
let i = i + 1
end
end
end
return true
end
t_init()
make a function called ticket_state_name takes n returns name
if n == 0 then
return "pending"
end
if n == 1 then
return "active"
end
return "done"
end
make a function called ticket_examples takes triples returns examples
let out = []
let i = 0
let n = to_num(list_len(triples))
while i < n do
let t = triples[i]
let b = new("Dict", "tsm_ex_" + pr_next_id())
send(b, "set", "state", t[0])
send(b, "set", "action", t[1])
let out = list_push(out, [b, t[2]])
let i = i + 1
end
return out
end
class Ticket {
field state = 0
make a function called apply takes self, action returns done
let b = new("Dict", "tsm_call_" + pr_next_id())
send(b, "set", "state", get(self, "state"))
send(b, "set", "action", action)
let ast = get("__vars", "ticket_transition_ast")
let registry = get("__vars", "ticket_registry")
let result = sbe_eval(ast, b, registry)
send(self, "set", "state", result[1])
return true
end
}
make a function called run_synth_demo_ticket_state_machine returns ok
let registry = pr_standard_registry()
# exhaustive 3x2 transition table: (state, action) -> next_state
let transition_examples = ticket_examples([
[0, 0, 1],
[0, 1, 0],
[1, 0, 1],
[1, 1, 2],
[2, 0, 2],
[2, 1, 2]
])
let transition_result = bidi_synthesize_from_examples(transition_examples, ["state", "action"], [], registry, ["cond", "eq_int"], 16)
check("transition logic derives (nested cond witness, 2 levels)", transition_result[0], "OK")
set_var("ticket_transition_ast", transition_result[1])
set_var("ticket_registry", registry)
print("derived transition AST: " + transition_result[1])
# Genuinely found, not hand-picked: cond(eq_int(state,action),
# cond(eq_int(state,0),1,2), state) -- comparing state==action looks
# semantically bizarre next to the intended "state==2 is terminal"
# reading, but it's still completely correct: with only 3 states x 2
# actions = 6 possible inputs, ALL given as training examples, there
# is no held-out input left to distinguish a "coincidental" formula
# from "the" formula -- any expression matching all 6 given pairs IS
# the complete, correct specification for every input this system
# could ever see. A genuinely different lesson from first_exceeding's
# own overfitting story: overfitting isn't a coherent risk once a
# domain is this small and exhaustively enumerated, it just means the
# search is free to land on whichever correct closed form it finds
# first, not necessarily the human-intuitive one.
# ---- real end-to-end state machine behaviour, via the derived logic alone ----
let t = new("Ticket", "t1")
check("starts pending", ticket_state_name(get(t, "state")), "pending")
send(t, "apply", 1)
check("pending + finish (invalid action) -> still pending", ticket_state_name(get(t, "state")), "pending")
send(t, "apply", 0)
check("pending + start -> active", ticket_state_name(get(t, "state")), "active")
send(t, "apply", 0)
check("active + start (invalid action) -> still active", ticket_state_name(get(t, "state")), "active")
send(t, "apply", 1)
check("active + finish -> done", ticket_state_name(get(t, "state")), "done")
send(t, "apply", 0)
check("done is terminal: + start -> still done", ticket_state_name(get(t, "state")), "done")
send(t, "apply", 1)
check("done is terminal: + finish -> still done", ticket_state_name(get(t, "state")), "done")
# A second, independent Ticket proves the transition logic is
# correctly reused per-instance, same discipline as the earlier
# object demo's second-account check.
let t2 = new("Ticket", "t2")
send(t2, "apply", 0)
check("a second, independent Ticket: pending + start -> active", ticket_state_name(get(t2, "state")), "active")
check("first ticket's own state is untouched by the second instance", ticket_state_name(get(t, "state")), "done")
t_report()
return get("__vars", "t_fail") == 0
end
run_synth_demo_ticket_state_machine()
# ---- PLANNED, not built: multi-hop event cascades ----
#
# Next tier after this one: a chain where one handler's OWN emitted
# event triggers a second, independent handler, which in turn emits a
# third event -- testing whether synthesized decisions compose across
# multiple hops, not just within one method (synth_demo_account_events.
# patlang's own composition was two derived pieces inside ONE handler;
# this would be the derived pieces spanning SEPARATE handlers instead).
#
# Concrete shape planned: extend the Ticket state machine above so that
# reaching "done" (a state the transition function ALREADY derives)
# emits "ticket_completed"; a separate, independent handler listens for
# that and decides (via its OWN small derived predicate, e.g. "was this
# ticket high-priority") whether to emit a further "notify_customer"
# event; a third, terminal handler just logs it. Real things to verify
# that a single-hop demo can't: (1) the cascade actually reaches the
# terminal handler (not just the first hop), (2) it does NOT fire
# further hops when an earlier decision says no (e.g. a non-priority
# ticket's completion should stop at hop one), (3) no infinite loop
# forms if a later handler's own logic could, even accidentally, re-
# trigger an earlier event in the chain -- worth a deliberate check,
# not just an assumption, given `when`/`emit` here has no built-in
# cycle guard. Would reuse this file's own Ticket/transition AST
# rather than a fresh domain, since the state-reaches-"done" trigger is
# already naturally in place.
PatLang source (the real, committed self_hosting/examples/synth_demo_ticket_state_machine.patlang — its library dependencies are inlined behind the scenes so it runs standalone in the browser with no file access, but what's shown here is the file exactly as committed)
# State machine domain -- the next complexity tier above synth_demo_
# account_events.patlang: rather than one conditional guarding a single
# decision, the transition function needs NESTED conditionals (guard on
# current state, then guard on action WITHIN that state), and the
# object wraps a genuinely small state machine (3 states, 2 actions)
# instead of a single numeric field.
#
# States are small integers (0=pending, 1=active, 2=done) rather than
# strings deliberately -- the interesting part of this demo is the
# NESTED-conditional transition logic itself (a real test of the
# combined partition+scan cond witness at 2 levels of nesting, not
# attempted in any earlier demo in this suite), not string-keyed
# decision tables (self_hosting/lib/synthesis_by_example.patlang's
# synthesize_lookup_from_examples already covers that shape). Actions:
# 0=start, 1=finish.
#
# next_state(state, action) =
# state == 2 ? 2 -- done is terminal
# : state == 0 ? (action == 0 ? 1 : 0) -- pending: start->active, else stays
# : (action == 1 ? 2 : 1) -- active: finish->done, else stays
#
# The 3x2 transition table is given EXHAUSTIVELY (6 examples covering
# every (state,action) pair) rather than leaving gaps to force
# generalization -- deliberately different from first_exceeding's own
# examples, and the more common real shape for a genuinely small,
# finite state machine's own spec: enumerate the whole table, don't
# leave corners undefined.
include "../lib/bidi_synthesis.patlang"
include "../lib/test.patlang"
t_init()
make a function called ticket_state_name takes n returns name
if n == 0 then
return "pending"
end
if n == 1 then
return "active"
end
return "done"
end
make a function called ticket_examples takes triples returns examples
let out = []
let i = 0
let n = to_num(list_len(triples))
while i < n do
let t = triples[i]
let b = new("Dict", "tsm_ex_" + pr_next_id())
send(b, "set", "state", t[0])
send(b, "set", "action", t[1])
let out = list_push(out, [b, t[2]])
let i = i + 1
end
return out
end
class Ticket {
field state = 0
make a function called apply takes self, action returns done
let b = new("Dict", "tsm_call_" + pr_next_id())
send(b, "set", "state", get(self, "state"))
send(b, "set", "action", action)
let ast = get("__vars", "ticket_transition_ast")
let registry = get("__vars", "ticket_registry")
let result = sbe_eval(ast, b, registry)
send(self, "set", "state", result[1])
return true
end
}
make a function called run_synth_demo_ticket_state_machine returns ok
let registry = pr_standard_registry()
# exhaustive 3x2 transition table: (state, action) -> next_state
let transition_examples = ticket_examples([
[0, 0, 1],
[0, 1, 0],
[1, 0, 1],
[1, 1, 2],
[2, 0, 2],
[2, 1, 2]
])
let transition_result = bidi_synthesize_from_examples(transition_examples, ["state", "action"], [], registry, ["cond", "eq_int"], 16)
check("transition logic derives (nested cond witness, 2 levels)", transition_result[0], "OK")
set_var("ticket_transition_ast", transition_result[1])
set_var("ticket_registry", registry)
print("derived transition AST: " + transition_result[1])
# Genuinely found, not hand-picked: cond(eq_int(state,action),
# cond(eq_int(state,0),1,2), state) -- comparing state==action looks
# semantically bizarre next to the intended "state==2 is terminal"
# reading, but it's still completely correct: with only 3 states x 2
# actions = 6 possible inputs, ALL given as training examples, there
# is no held-out input left to distinguish a "coincidental" formula
# from "the" formula -- any expression matching all 6 given pairs IS
# the complete, correct specification for every input this system
# could ever see. A genuinely different lesson from first_exceeding's
# own overfitting story: overfitting isn't a coherent risk once a
# domain is this small and exhaustively enumerated, it just means the
# search is free to land on whichever correct closed form it finds
# first, not necessarily the human-intuitive one.
# ---- real end-to-end state machine behaviour, via the derived logic alone ----
let t = new("Ticket", "t1")
check("starts pending", ticket_state_name(get(t, "state")), "pending")
send(t, "apply", 1)
check("pending + finish (invalid action) -> still pending", ticket_state_name(get(t, "state")), "pending")
send(t, "apply", 0)
check("pending + start -> active", ticket_state_name(get(t, "state")), "active")
send(t, "apply", 0)
check("active + start (invalid action) -> still active", ticket_state_name(get(t, "state")), "active")
send(t, "apply", 1)
check("active + finish -> done", ticket_state_name(get(t, "state")), "done")
send(t, "apply", 0)
check("done is terminal: + start -> still done", ticket_state_name(get(t, "state")), "done")
send(t, "apply", 1)
check("done is terminal: + finish -> still done", ticket_state_name(get(t, "state")), "done")
# A second, independent Ticket proves the transition logic is
# correctly reused per-instance, same discipline as the earlier
# object demo's second-account check.
let t2 = new("Ticket", "t2")
send(t2, "apply", 0)
check("a second, independent Ticket: pending + start -> active", ticket_state_name(get(t2, "state")), "active")
check("first ticket's own state is untouched by the second instance", ticket_state_name(get(t, "state")), "done")
t_report()
return get("__vars", "t_fail") == 0
end
run_synth_demo_ticket_state_machine()
# ---- PLANNED, not built: multi-hop event cascades ----
#
# Next tier after this one: a chain where one handler's OWN emitted
# event triggers a second, independent handler, which in turn emits a
# third event -- testing whether synthesized decisions compose across
# multiple hops, not just within one method (synth_demo_account_events.
# patlang's own composition was two derived pieces inside ONE handler;
# this would be the derived pieces spanning SEPARATE handlers instead).
#
# Concrete shape planned: extend the Ticket state machine above so that
# reaching "done" (a state the transition function ALREADY derives)
# emits "ticket_completed"; a separate, independent handler listens for
# that and decides (via its OWN small derived predicate, e.g. "was this
# ticket high-priority") whether to emit a further "notify_customer"
# event; a third, terminal handler just logs it. Real things to verify
# that a single-hop demo can't: (1) the cascade actually reaches the
# terminal handler (not just the first hop), (2) it does NOT fire
# further hops when an earlier decision says no (e.g. a non-priority
# ticket's completion should stop at hop one), (3) no infinite loop
# forms if a later handler's own logic could, even accidentally, re-
# trigger an earlier event in the chain -- worth a deliberate check,
# not just an assumption, given `when`/`emit` here has no built-in
# cycle guard. Would reuse this file's own Ticket/transition AST
# rather than a fresh domain, since the state-reaches-"done" trigger is
# already naturally in place.
usually a couple of seconds
(not run yet)
Real transcript, run on the build machine:
Output (click to expand)
bidi_synthesize_from_examples: size=2 at 1788381690935 bidi_synthesize_from_examples: size=3 at 1788381690940 bidi_synthesize_from_examples: size=4 at 1788381690953 bidi_synthesize_from_examples: size=5 at 1788381690958 bidi_synthesize_from_examples: size=6 at 1788381690963 ok: transition logic derives (nested cond witness, 2 levels) derived transition AST: [Call, cond, [[Call, eq_int, [[Input, state], [Input, action]]], [Call, cond, [[Call, eq_int, [[Input, state], [Const, 0]]], [Const, 1], [Const, 2]]], [Input, state]]] ok: starts pending ok: pending + finish (invalid action) -> still pending ok: pending + start -> active ok: active + start (invalid action) -> still active ok: active + finish -> done ok: done is terminal: + start -> still done ok: done is terminal: + finish -> still done ok: a second, independent Ticket: pending + start -> active ok: first ticket's own state is untouched by the second instance tests: 10 passed, 0 failed ALL TESTS PASSED true
A held-out case, and a structural contract that rules out the shortcut
ThisThis third demo extends the same transition table to 3 actions instead of 2 (9 examples total, still exhaustive), then derives it twice: once with no restriction (the baseline, which again finds the state-vs-action shortcut), and once with bidi_contract_fn set to a predicate that rules out any node directly comparing state to action, anywhere in the tree. Both results are independently verified against all nine table entries before the comparison is trusted.
Given state = pending, action = start Then next_state = active
Given state = pending, action = finish Then next_state = pending
Given state = pending, action = pause Then next_state = pending
Given state = active, action = start Then next_state = active
Given state = active, action = finish Then next_state = done
Given state = active, action = pause Then next_state = pending
Given state = done, action = start Then next_state = done
Given state = done, action = finish Then next_state = done
Given state = done, action = pause Then next_state = doneNot click-to-run here, unlike the two demos above: the contracted search alone takes a little over a minute on the build machine, and every WebAssembly module on this site runs synchronously on the browser's own main thread once started — there is no worker thread to keep the page responsive while it runs, so starting it here would freeze this tab for that entire time with no way to cancel. The real transcript below is unedited, timestamps included, so the size=6-to-7 jump where the contract starts rejecting the shortcut and searching further is visible directly in the numbers, not just asserted.
PatLang source (the real, committed self_hosting/examples/synth_demo_structural_contract.patlang)
# Structural contracts on derived functions -- a generalization of
# primitive_registry.patlang's existing per-argument arg_contracts to
# a whole-function output constraint, checked on the ASSEMBLED
# candidate rather than on one argument in isolation.
#
# Motivation: synth_demo_ticket_state_machine.patlang's own exhaustive
# 3x2 transition table derives cond(eq_int(state,action), cond(eq_int(
# state,0),1,2), state) -- fully correct (the domain is exhaustively
# specified, so no held-out case can distinguish it from any other
# correct formula) but semantically odd: it compares state directly to
# action, which happens to work only because the numbers line up, not
# because that's what the transition logic actually means. Several
# earlier attempts to force a more human-intuitive result by varying
# the examples (more inputs, disjoint integer ranges, string-typed
# actions) all failed to change this -- either the search still found
# a different coincidental shortcut, or it ran out of memory looking
# for one. This demo tests the next lever instead: don't hope a
# different formula shows up, RULE OUT the specific shortcut directly.
#
# bidi_contract_ok(node) (self_hosting/lib/bidi_synthesis.patlang) is
# an optional check applied to bidi_try_cond_combined's ASSEMBLED
# cond(test, a, b) candidates: if set_var("bidi_contract_fn", name) has
# been called, a candidate is only accepted when apply(name, candidate)
# is true, and rejected candidates simply lose the partition -- the
# search moves on and tries other partitions/branch pairs, it doesn't
# stop. This mirrors arg_contracts' own accept-or-skip discipline
# (primitive_registry.patlang), just applied to the whole node instead
# of one argument. Purely additive: unset (the default), every existing
# caller behaves exactly as before -- this file is the only caller that
# sets it.
#
# The contract used here bans a Call node whose two DIRECT arguments
# are exactly Input(state) and Input(action) compared to each other,
# anywhere in the tree -- narrow enough that a correct formula (which
# legitimately needs to reference both state and action, just never
# directly against each other) is not ruled out entirely, only the
# specific coincidental shortcut is.
include "../lib/bidi_synthesis.patlang"
include "../lib/test.patlang"
t_init()
make a function called ast_contains_pair takes node, a, b returns yes
let tag = node[0]
if tag == "Call" then
let args = node[2]
if to_num(list_len(args)) == 2 then
let x = args[0]
let y = args[1]
let is_ab = (x[0] == "Input") and (x[1] == a) and (y[0] == "Input") and (y[1] == b)
let is_ba = (x[0] == "Input") and (x[1] == b) and (y[0] == "Input") and (y[1] == a)
if is_ab or is_ba then
return true
end
end
let i = 0
let n = to_num(list_len(args))
while i < n do
if ast_contains_pair(args[i], a, b) then
return true
end
let i = i + 1
end
return false
end
return false
end
make a function called contract_no_direct_state_action_compare takes node returns ok
return not ast_contains_pair(node, "state", "action")
end
make a function called transition_examples takes triples returns examples
let out = []
let i = 0
let n = to_num(list_len(triples))
while i < n do
let t = triples[i]
let b = new("Dict", "sc_ex_" + pr_next_id())
send(b, "set", "state", t[0])
send(b, "set", "action", t[1])
let out = list_push(out, [b, t[2]])
let i = i + 1
end
return out
end
make a function called run_synth_demo_structural_contract returns ok
let registry = pr_standard_registry()
# exhaustive 3x3 transition table -- same shape as synth_demo_ticket_
# state_machine.patlang's own 3x2 table, extended to a 3rd action so
# the coincidental eq_int(state,action) shortcut (which needed states
# and actions to line up 1:1) is available to find again here, giving
# the contract something real to rule out.
let examples = transition_examples([
[0, 0, 1], [0, 1, 0], [0, 2, 0],
[1, 0, 1], [1, 1, 2], [1, 2, 0],
[2, 0, 2], [2, 1, 2], [2, 2, 2]
])
set_var("bidi_contract_fn", false)
let baseline = bidi_synthesize_from_examples(examples, ["state", "action"], [], registry, ["cond", "eq_int"], 24)
check("baseline (no contract) derives", baseline[0], "OK")
check("baseline coincidentally compares state directly to action", ast_contains_pair(baseline[1], "state", "action"), true)
set_var("bidi_contract_fn", "contract_no_direct_state_action_compare")
let contracted = bidi_synthesize_from_examples(examples, ["state", "action"], [], registry, ["cond", "eq_int"], 24)
set_var("bidi_contract_fn", false)
check("contracted derivation still succeeds", contracted[0], "OK")
check("contracted result never directly compares state to action", ast_contains_pair(contracted[1], "state", "action"), false)
print("baseline AST: " + baseline[1])
print("contracted AST: " + contracted[1])
# Verify the contracted formula against the FULL transition table
# directly (not just the training examples it was derived from --
# here they're the same 9 cases, since the domain is exhaustively
# specified, but re-checking independently of sbe_matches_all's own
# internal bookkeeping is the real test of correctness).
let i = 0
let n = to_num(list_len(examples))
let all_correct = true
while i < n do
let ex = examples[i]
let result = sbe_eval(contracted[1], ex[0], registry)
if result[1] != ex[1] then
let all_correct = false
end
let i = i + 1
end
check("contracted formula matches every one of the 9 transition-table entries", all_correct, true)
# Honest finding, not a hidden caveat: the contract achieves exactly
# what it was asked to (rule out the ONE named pattern) but does not
# make the result more human-intuitive in general -- it can just as
# easily trade one coincidence for a more convoluted one, since
# nothing about "smallest AST that satisfies the contract" implies
# "the AST a person would have written." Ruling out a specific known
# bad pattern is a real, useful capability; it is not a general fix
# for search landing on non-intuitive-but-correct formulas.
print("size: baseline=" + sbe_size(baseline[1]) + " contracted=" + sbe_size(contracted[1]))
t_report()
return get("__vars", "t_fail") == 0
end
run_synth_demo_structural_contract()
Real transcript, run on the build machine:
Output (click to expand)
bidi_synthesize_from_examples: size=2 at 1788382151697 bidi_synthesize_from_examples: size=3 at 1788382151744 bidi_synthesize_from_examples: size=4 at 1788382151800 bidi_synthesize_from_examples: size=5 at 1788382151848 bidi_synthesize_from_examples: size=6 at 1788382151898 ok: baseline (no contract) derives ok: baseline coincidentally compares state directly to action bidi_synthesize_from_examples: size=2 at 1788382175684 bidi_synthesize_from_examples: size=3 at 1788382175729 bidi_synthesize_from_examples: size=4 at 1788382175785 bidi_synthesize_from_examples: size=5 at 1788382175831 bidi_synthesize_from_examples: size=6 at 1788382175877 bidi_synthesize_from_examples: size=7 at 1788382201694 bidi_synthesize_from_examples: size=8 at 1788382225606 ok: contracted derivation still succeeds ok: contracted result never directly compares state to action baseline AST: [Call, cond, [[Call, eq_int, [[Input, state], [Input, action]]], [Call, cond, [[Call, eq_int, [[Input, state], [Const, 0]]], [Const, 1], [Const, 2]]], [Call, cond, [[Call, eq_int, [[Input, action], [Const, 2]]], [Const, 0], [Input, state]]]]] contracted AST: [Call, cond, [[Call, eq_int, [[Input, state], [Call, cond, [[Call, eq_int, [[Input, state], [Const, 1]]], [Input, action], [Const, 2]]]]], [Const, 2], [Call, cond, [[Call, eq_int, [[Input, action], [Const, 0]]], [Const, 1], [Const, 0]]]]] ok: contracted formula matches every one of the 9 transition-table entries size: baseline=16 contracted=16 tests: 5 passed, 0 failed ALL TESTS PASSED true
See also
Example-DrivenExample-Driven Synthesis covers how the search itself works, including the bidirectional witness functions and the structural-contract mechanism demonstrated on this page. The project journey (Acts LVIII-LXV) covers the session this work came out of, warts included. PatLang BDD Framework covers the separate Given/When/Then .feature-file runner referenced throughout — the examples on this page are given the same way in spirit, though these three demos build their example sets directly in code rather than through a parsed .feature file.