213cedf0b5
The trailing-`!`-after-the-value-type spelling (`-> T !`, `-> Tuple(A,B) !`) was a
redundant second way to write a failable return that the parser folded into the
same AST as the parenthesized `(T, !)` / `(A, B, !)` result list. Remove it so
there is ONE canonical spelling: the error channel always rides as the last slot
of the parenthesized list.
- parser: `parseFnReturnType` no longer folds a trailing `!` after a value type —
it rejects it with a located diagnostic ("a failable return is written `(T, !)`
… not `T !`"). This one chokepoint covers fn declarations, lambdas, fn-pointer
types `(A) -> R`, and closure types `Closure(A) -> R`. The error-ONLY `-> !` /
`-> !ErrSet` form is unaffected (parsed by parseTypeExpr as an error_type_expr).
- migrated every usage to canonical form across library/ + examples/ + issues/ +
tests/: `-> T !E` → `-> (T, !E)`; the value-carrying `-> Tuple(A, B) !` (which
FLATTENED to a multi-value failable) → `-> (A, B, !)`, preserving behavior. A
genuine single-tuple-value failable stays `-> (Tuple(A,B), !)`.
- parser unit tests: the "bare form folds" tests become "bare form is rejected";
canonical-form parse tests retained.
- docs: specs.md §12 + scattered refs and readme.md updated to the `(T, !)` form.
Behavior-preserving (the bare form was sugar for the same AST). Adversarial review
confirmed: rejection complete across all positions, every canonical form works on
both success/error paths, error-only `-> !` intact, no crashes. Full suite green
(unit tests + 850 corpus examples).
37 lines
1.7 KiB
Plaintext
37 lines
1.7 KiB
Plaintext
// Program-wide inferred-`!` union per closure shape (ERR E5.1 sub-feature 2).
|
|
// All occurrences of `Closure(i32) -> (i32, !)` share ONE inferred error set;
|
|
// every bare-`!` closure literal of that shape unions its raised tags in. A
|
|
// `try slot(x)` against any matching-shape slot widens against that union — so
|
|
// a caller whose named set covers { Negative, Other } type-checks, and the
|
|
// error channel actually carries each closure's own tag at runtime.
|
|
|
|
#import "modules/std.sx";
|
|
|
|
All :: error { Negative, Other }
|
|
|
|
// `h` is a bare-`!` Closure slot; the caller declares the union as `!All`.
|
|
dispatch :: (h: Closure(i32) -> (i32, !), x: i32) -> (i32, !All) {
|
|
return try h(x);
|
|
}
|
|
|
|
main :: () -> i32 {
|
|
gpa := GPA.init();
|
|
push Context.{ allocator = xx gpa } {
|
|
// Two literals of the SAME shape raising DIFFERENT tags both feed the
|
|
// one shared `Closure(i32)->(i32,!)` union node.
|
|
handlers : List(Closure(i32) -> (i32, !)) = .{};
|
|
handlers.append(closure((x: i32) -> (i32, !) { if x < 0 { raise error.Negative; } return x * 2; }));
|
|
handlers.append(closure((x: i32) -> (i32, !) { if x == 0 { raise error.Other; } return x + 100; }));
|
|
|
|
// success paths
|
|
print("ok0={}\n", dispatch(handlers.items[0], 5) catch (e) 0); // 10
|
|
print("ok1={}\n", dispatch(handlers.items[1], 7) catch (e) 0); // 107
|
|
|
|
// failure paths: each closure raises its own tag, which propagates
|
|
// through `try` and is absorbed by the call-site `catch` fallback
|
|
print("err0={}\n", dispatch(handlers.items[0], -1) catch (e) -1); // raised Negative → -1
|
|
print("err1={}\n", dispatch(handlers.items[1], 0) catch (e) -2); // raised Other → -2
|
|
}
|
|
return 0;
|
|
}
|