Brummel
df5b76bd65
Third stdlib module. Either<e, a> is the first 2-type-var data def, and the eliminator `either : (e -> c) -> (a -> c) -> Either<e, a> -> c` the first fn with three type vars on top of the data — the deepest polymorphism shipped end-to-end so far. Five combinators: from_right, is_left, is_right, map_right, either. Demo exercises every one and runs to deterministic output. IR shows six distinct monomorphisations including two `from_right` variants (Left=Int vs Left=$u depending on call site) and `either__I_I_I`. No new compiler bugs surfaced: 14a / 14h / 15b coverage was wide enough to handle 2-type-var data plus 3-type-var fns out of the box. Discovered (queued as 15e): `ail render` and `ail parse` are not symmetric. Form-(A) printer in ailang_surface::print is the actual inverse of `parse` (round-trip test covers it across all 25 fixtures including std_either) but is not exposed via the CLI; `render` still calls the older ailang_core::pretty::module printer. Tests: 89/89 (was 88, +1 e2e for std_either_demo). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
32 lines
1.5 KiB
Plaintext
32 lines
1.5 KiB
Plaintext
; Iter 15d — third consumer demo.
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; Imports std_either, exercises all five combinators. First demo to
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; pass two function arguments to a single combinator (the eliminator
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; `either`); first to drive a 3-type-var polymorphic fn end-to-end.
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(module std_either_demo
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(import std_either)
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(fn inc
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(doc "Add 1 to an Int. Used as the function arg to map_right and either.")
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(type (fn-type (params (con Int)) (ret (con Int))))
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(params x)
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(body (app + x 1)))
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(fn main
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(doc "Drive each std_either combinator. Expected outputs (per line): 42, 99, true, true, 42, 6, 101.")
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(type (fn-type (params) (ret (con Unit)) (effects IO)))
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(params)
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(body
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(seq (do io/print_int (app std_either.from_right 0 (term-ctor std_either.Either Right 42)))
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(seq (do io/print_int (app std_either.from_right 99 (term-ctor std_either.Either Left 7)))
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(seq (do io/print_bool (app std_either.is_left (term-ctor std_either.Either Left 7)))
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(seq (do io/print_bool (app std_either.is_right (term-ctor std_either.Either Right 42)))
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(seq (do io/print_int (app std_either.from_right 0
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(app std_either.map_right inc
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(term-ctor std_either.Either Right 41))))
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(seq (do io/print_int (app std_either.either inc inc
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(term-ctor std_either.Either Left 5)))
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(do io/print_int (app std_either.either inc inc
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(term-ctor std_either.Either Right 100))))))))))))
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