Files
sx/examples/errors/1039-errors-failable-closure-literal.sx
agra 989e18b760 feat: tuple syntax cutover — Tuple(...) type + .(...) value
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.
2026-06-25 17:53:57 +03:00

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// Failable closure literals (ERR E5.1): a `closure(...)` literal may declare a
// failable return type — `-> (T, !)` / `-> !Named` — in both block and arrow
// body forms, and `raise` inside. Called directly through the bound local, the
// error channel is consumed by `catch` / `or`; passed as a `Closure(...)`
// parameter, it composes through the callee (here absorbed with `catch`).
// (A capturing closure into a bare `(T)->U` slot, and a failable closure into a
// non-failable slot, are rejected — see issue 0060 / the FFI-boundary rule.)
#import "modules/std.sx";
E :: error { Neg }
runwith :: (cb: Closure(i64) -> i64 !E, n: i64) -> i64 { return cb(n) catch (e) -1; }
main :: () -> i32 {
// block-body and arrow-body failable closures, called directly
m := closure((x: i64) -> i64 !E { if x < 0 { raise error.Neg; } return x * 2; });
n := closure((x: i64) -> i64 !E => x + 1);
print("{} {} {} {}\n", m(5) catch (e) 0, m(-1) catch (e) 99, m(-1) or 7, n(40) catch (e) 0); // 10 99 7 41
// failable closure passed as a Closure(...) parameter
print("param ok={} err={}\n", runwith(m, 5), runwith(m, -1)); // 10 -1
return 0;
}