83ec2536af
try foo() catch (e) { } // legal
try foo() catch e { } // parse error with a migration hint
Same capture style as the for-loop. All four catch shapes keep working
with the parenthesized binding — block, bare-expression body, and the
== match sugar — and the no-binding forms are unchanged. onfail follows
the same rule (onfail (e) { }); its expression-cleanup form is
disambiguated by the paren-group-before-brace lookahead, so
onfail (f()); stays an expression cleanup.
AST unchanged; the printer renders the parens; the #run escape help
text updated. Corpus migrated (57 catch + 3 onfail bindings, in-source
parser test strings, specs incl. grammar rules, readme untouched —
no catch examples there).
Regression: examples/1157-diagnostics-catch-binding-needs-parens.sx;
re-captured stderr for 1010/1013/1037/1123 (migrated source echoed in
carets + help text).
30 lines
1.4 KiB
Plaintext
30 lines
1.4 KiB
Plaintext
// Generic function with a value-carrying `!` return composes (ERR E5.1
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// sub-feature 8). A `$T: Type` generic whose return is `(T, !E)` monomorphizes
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// per call: `return try f()` propagates the closure's error, and each
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// monomorphization's success value flows through as the concrete `T`.
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// (Regression: confirms issue 0062 was an invalid-syntax repro — the bug only
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// appeared with the non-generic `T: Type` form; the `$T` form works.)
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#import "modules/std.sx";
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E :: error { Bad }
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wrap :: ($T: Type, f: Closure() -> (T, !E)) -> (T, !E) { return try f(); }
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main :: () -> s32 {
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// success, consumed by catch
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print("catch={}\n", wrap(s32, closure(() -> (s32, !E) { return 7; })) catch (e) -1); // 7
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// success, consumed by destructure (binds value + error slot); the value
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// slot is read only under an `if !err` guard (ERR E1.8 path-sensitivity)
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r, err := wrap(s32, closure(() -> (s32, !E) { return 9; }));
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if !err { print("destr={} ok=true\n", r); } // destr=9 ok=true
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// failure path: the raised tag propagates through the generic `try`
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print("fail={}\n", wrap(s32, closure(() -> (s32, !E) { raise error.Bad; }) ) catch (e) -1); // -1
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// a second monomorphization at a different T
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print("u8={}\n", wrap(u8, closure(() -> (u8, !E) { return 200; })) catch (e) 0); // 200
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return 0;
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}
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