989e18b760
Replace the bare-paren tuple grammar with explicit, position-unambiguous
forms, mirroring how structs work:
type `(A, B)` -> `Tuple(A, B)` (named keeps `:`)
value `(a, b)` -> `.(a, b)` (named uses `=`)
typed (new) -> `Tuple(A, B).(a, b)` (like `Point.{...}`)
failable `-> (T, !)` -> `-> T !`
`-> (T1, T2, !)`-> `-> Tuple(T1, T2) !` (channel outside Tuple)
Bare `(...)` is now grouping only, everywhere; a comma in bare parens is a
hard error with a migration hint. Grouping, function types `(A, B) -> R`,
param lists, lambdas, and match bindings are unaffected.
`Tuple(...)` is strictly a TYPE in every position (including `size_of` /
`type_info` args); a tuple VALUE comes only from `.(...)` (anonymous) or
`Tuple(...).(...)` (explicitly typed). A bare `Tuple(1, 2)` is a tuple
type with non-type elements -> rejected.
The ~110 tuple-bearing corpus files were migrated with a one-shot
AST-aware migrator (the `sx migrate` tool from the prior commit, removed
here). New examples: 0130 (new syntax), 0131 (typed construction), 1060
(named-tuple failable return). 1116 golden updated for the new hint text.
37 lines
1.4 KiB
Plaintext
37 lines
1.4 KiB
Plaintext
// Value-carrying failable functions (ERR step E2.1a — the producer side of the
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// error-channel tuple ABI). A `-> (T, !E)` function returns EITHER a value OR
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// an error: `return v;` yields the success tuple `{v, 0}` (the compiler appends
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// the no-error slot), and `raise error.X` yields `{undef, tag}` (value slot
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// undefined, error slot = the tag). Today the result is consumed by
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// destructuring `v, err := f()` (which extracts both slots); the value-carrying
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// `try` / `catch` consumers land in E2.1b.
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#import "modules/std.sx";
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E :: error { Bad, Empty }
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parse :: (n: i32) -> i32 !E {
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if n < 0 { raise error.Bad; }
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if n == 0 { raise error.Empty; }
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return n * 10; // success → {n*10, 0}
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}
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main :: () -> i32 {
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r : i32 = 0;
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// The value slot is live only where the error is proven absent (ERR E1.8):
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// read `v1` under an `if !e1` guard, not after a bare tag-compare.
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v1, e1 := parse(5); // success → v1 = 50, e1 = no error
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if !e1 { r = r + v1; } // success → +50
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v2, e2 := parse(-1); // Bad
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if e2 == error.Bad { r = r + 7; } // true → +7
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if e2 == error.Empty { r = r + 200; } // false
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v3, e3 := parse(0); // Empty
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if e3 == error.Empty { r = r + 3; } // true → +3
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print("value-failable result: {}\n", r); // 50 + 7 + 3 = 60
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return r;
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}
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