v4.5.0

Two new portable constructs — @@fsm recognizers and @@:self — plus verbatim type/value passthrough and exception-free C++/Swift output.

4.5.0 is a feature release with two headline additions and a set of contract and portability fixes. @@fsm brings a regular-language recognizer construct to all 17 targets at full parity; @@:self makes self-reference portable; verbatim passthrough closes the last gap between the “Frame has no type system” contract and what codegen did; and C++/Swift core output is now exception-free so it builds where exceptions are compiled out (notably Godot web). This release has breaking hard-cuts, all mechanical to fix; Frame is pre-public-beta, so no published program is affected. See the migration guide.

Highlights

  • @@fsm — finite-state recognizers, all 17 languages (RFC-0042). A new top-level construct that compiles a regular-language recognizer to a Pike-VM-backed state machine, emitted at full behavioral parity on every backend. It implements the RE2 dialect across the regular-language feature set: literal / character-class / Unicode \d \w \s alphabets (and \p{…} via @@[allow(unicode_classes)]); | ordered choice; greedy and lazy quantifiers; edge and interior anchors; character-, byte-, and Unicode-aware word boundaries \b/\B; inline flags (?i)/(?m)/(?s) and scoped (?ims:…)/(?-i:…); captures with action blocks; when-conditional and stage-reference transition targets; a token alphabet; multi-match states; embedding; and Mode-C sub-fsm call-out. The action-body statement grammar is specified in RFC-0050.
  • @@:self — portable, blessed self-reference (RFC-0046). Write @@:self.field, @@:self.action(), and @@:self.field.method() (embed calls), including inside return expressions and across systems; framec lowers each to its target’s native self/this idiom on all 17 backends. This replaces the per-language textual self-rewriters with segment-driven lowering.
  • Verbatim type & value passthrough (#61, #59, #62). The leftover type-alias tables (int→i64, str→String, float→f64, …) and the state-variable “portable init” wrapping ("" → String::from("")) are gone. You write your target’s own type names and init values and they reach the generated code unchanged — which also fixes a float-literal corruption bug those layers hid ($.x: f64 = 0.0 previously emitted 0). Section comments emit verbatim too.
  • Exception-free C++/Swift core output (RFC-0049). Core dispatch maintains its context-stack invariant with each language’s idiomatic scope-cleanup (RAII / defer) instead of a mandatory catch-and-rethrow, so generated C++ now compiles and links under -fno-exceptions — unblocking Godot web GDExtensions. The opt-in @@[persist] and @@[async] features keep a compiled-out throw/abort fallback. Exceptions are optional, not the rule.

Breaking changes

See the migration guide for the canonical→native table, worked before/after, and the state-var-initializer change.

  • Type annotations are no longer aliased. A source that wrote a Frame-canonical name (: int, : str, : float) and relied on framec mapping it to the target’s native type now emits that name verbatim. Where the canonical name is native nothing changes; where it isn’t — notably str everywhere, and int/float on Rust — write the native name (String/i64/f64, …).
  • State-variable init values are no longer wrapped. A String-typed state var initialized with a bare "" now emits "" instead of String::from(""). Write the native init value for the target.
  • State variables now require an explicit initializer (#84, E610). The synthesized-default value table was removed. A state var declared without an initializer is an E610 error — give it the native init value for its declared type, exactly as for a domain field.

Action required

Sources already written in native type names and native init values, with every state variable initialized, generate identical output to 4.4.x and need nothing. Otherwise, rewrite the affected annotations/values to your target’s native spelling and add the missing initializers — see the migration guide for the per-target table. The new @@fsm and @@:self constructs are additive; no existing source needs to adopt them.

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