Brummel
7b92719244
First iteration of the mut-local milestone (foundation step on the
Stateful-islands roadmap path). Lands the schema + surface tier:
Term::Mut, Term::Assign, and the nested MutVar struct become
first-class AST nodes that round-trip cleanly through Form A.
Typecheck and codegen recognition are deferred to mut.2 and mut.3
per the spec's out-of-iteration boundary; reaching either dispatch
entry point with these variants produces CheckError::Internal /
CodegenError::Internal with a 'deferred to iter mut.{2,3}' message.
Concretely:
- crates/ailang-core/src/ast.rs: two new Term variants behind
#[serde(tag = 't')]; pub struct MutVar { name, ty, init } adjacent
to Arm. Two canonical-bytes pin tests for the explicit-empty-vars
serialisation and the assign round-trip.
- ~25 substantive Term-walker arms across ailang-core/desugar,
ailang-core/workspace, ailang-check (lib + lift + linearity + mono
+ pre_desugar_validation + reuse_shape + uniqueness),
ailang-codegen (escape + lambda + lib), ailang-prose, and
crates/ail/src/main.rs. Universal policy: substantive recurse-into-
children at every site; only the two dispatch entry points
(synth in ailang-check, lower_term in ailang-codegen) stub with
Internal-error. One test-side walker arm in
crates/ail/tests/codegen_import_map_fallback_pin.rs not
enumerated by the plan was added as well (defensive recursion).
- ailang-surface: parse_mut + parse_assign helpers; Term::Mut
body desugared from a flat statement sequence into a right-folded
Term::Seq chain inside the JSON-AST. Print arms in print.rs match
the parser convention. EBNF prologue + crates/ailang-core/specs/
form_a.md productions updated. Four new parser pin tests cover
the empty-mut, single-var, body-required, and vars-only-no-body
cases.
- Drift + coverage tests extended: design_schema_drift.rs adds two
exemplars + match arms; schema_coverage.rs adds two VariantTag
entries + EXPECTED_VARIANTS + visit_term arms; spec_drift.rs adds
two exemplars + match arms. DESIGN.md §'Term (expression)' gets
jsonc-blocked schemas for the two new variants.
- examples/mut.ail: six-fn round-trip fixture exercising empty mut,
single-var, two-var, nested-shadow, and the four supported scalar
return types (Int, Float, Bool, Unit). The round_trip auto-glob
and schema_coverage corpus walker both pick it up.
Plan deviation: the plan named lib.rs:2572 as the typecheck
dispatch stub site, but that line is actually verify_tail_positions
(substantive walker). The real dispatch is synth (3403-area, stub
at 3489); the orchestrator routed correctly.
Tests: 564 → 579 green; cargo build green; round-trip green for
the new fixture; all drift + coverage tests green.
Journal: docs/journals/2026-05-15-iter-mut.1.md.
Refs: docs/specs/2026-05-15-mut-local.md, docs/plans/2026-05-15-iter-mut.1.md.
63 lines
1.6 KiB
Plaintext
63 lines
1.6 KiB
Plaintext
(module mut
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(fn mut_empty
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(doc "Iter mut.1 — empty mut block; body is a single Int literal.")
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(type (fn-type (params) (ret (con Int))))
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(params)
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(body (mut 0)))
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(fn mut_single_var
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(doc "Iter mut.1 — one var, one assign, final expression reads the var.")
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(type (fn-type (params) (ret (con Int))))
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(params)
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(body
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(mut
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(var x (con Int) 0)
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(assign x (app + x 1))
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x)))
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(fn mut_two_vars
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(doc "Iter mut.1 — two vars, two assigns, final expression combines them.")
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(type (fn-type (params) (ret (con Float))))
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(params)
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(body
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(mut
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(var sum (con Float) 0.0)
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(var count (con Int) 0)
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(assign sum (app + sum 1.0))
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(assign count (app + count 1))
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(app + sum (app int_to_float count)))))
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(fn mut_nested_shadow
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(doc "Iter mut.1 — outer var shadowed by inner mut block's var of the same name.")
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(type (fn-type (params) (ret (con Int))))
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(params)
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(body
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(mut
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(var x (con Int) 10)
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(assign x (app + x 1))
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(mut
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(var x (con Int) 100)
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(assign x (app + x 1))
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x))))
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(fn mut_returns_bool
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(doc "Iter mut.1 — exercise Bool as a supported scalar var type.")
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(type (fn-type (params) (ret (con Bool))))
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(params)
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(body
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(mut
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(var flag (con Bool) false)
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(assign flag true)
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flag)))
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(fn mut_returns_unit
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(doc "Iter mut.1 — exercise Unit as the supported scalar zero case.")
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(type (fn-type (params) (ret (con Unit))))
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(params)
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(body
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(mut
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(var u (con Unit) (lit-unit))
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(assign u (lit-unit))
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u))))
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