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).
25 lines
1.2 KiB
Plaintext
25 lines
1.2 KiB
Plaintext
// Failable closure literals (ERR E5.1): a `closure(...)` literal may declare a
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// failable return type — `-> (T, !)` / `-> !Named` — in both block and arrow
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// body forms, and `raise` inside. Called directly through the bound local, the
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// error channel is consumed by `catch` / `or`; passed as a `Closure(...)`
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// parameter, it composes through the callee (here absorbed with `catch`).
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// (A capturing closure into a bare `(T)->U` slot, and a failable closure into a
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// non-failable slot, are rejected — see issue 0060 / the FFI-boundary rule.)
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#import "modules/std.sx";
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E :: error { Neg }
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runwith :: (cb: Closure(s64) -> (s64, !E), n: s64) -> s64 { return cb(n) catch (e) -1; }
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main :: () -> s32 {
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// block-body and arrow-body failable closures, called directly
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m := closure((x: s64) -> (s64, !E) { if x < 0 { raise error.Neg; } return x * 2; });
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n := closure((x: s64) -> (s64, !E) => x + 1);
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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
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// failable closure passed as a Closure(...) parameter
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print("param ok={} err={}\n", runwith(m, 5), runwith(m, -1)); // 10 -1
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return 0;
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}
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