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.
31 lines
1.0 KiB
Plaintext
31 lines
1.0 KiB
Plaintext
// Failable error-slot discard rejection (ERR step E1.8 — discard slice). The
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// error slot of a value-carrying failable cannot be dropped on a bare
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// destructure: it must be bound (`v, err := …`) and handled, or the failure
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// routed through `try` / `catch` / `or value` (all of which strip the error
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// channel, so they don't reach this check). Two rejected shapes here:
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// (1) omitting the error slot entirely (fewer names than slots), and
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// (2) binding it to `_`.
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// This file is expected to FAIL compilation (exit 1).
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//
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// Run: ./zig-out/bin/sx run examples/236-failable-discard-reject.sx
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#import "modules/std.sx";
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E :: error { Bad, Empty }
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pair :: (n: i32) -> Tuple(i32, i32) !E {
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if n < 0 { raise error.Bad; }
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return .(n, n + 1);
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}
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parse :: (n: i32) -> i32 !E {
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if n < 0 { raise error.Bad; }
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return n * 2;
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}
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main :: () -> i32 {
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a, b := pair(5); // ERROR: error slot omitted (3 slots, 2 names)
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v, _ := parse(5); // ERROR: error slot discarded with `_`
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return a + b + v;
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}
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