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).
35 lines
1.7 KiB
Plaintext
35 lines
1.7 KiB
Plaintext
// Failable closure composition (ERR E5.1): a closure LITERAL passed as a
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// function-type argument and called inside the callee. Covers a bare failable
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// fn-type param (`cb: (T) -> (U, !)`), the idiomatic `Closure(...)` param
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// (try-propagated), and ∅-widening of a NON-failable closure literal into a
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// failable slot (the generated adapter wraps the value into `{value, 0}`).
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//
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// NOTE: the adapter is generated when the closure LITERAL flows directly into
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// the bare-fn slot. Passing a pre-bound closure *variable* into a bare-fn slot
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// is a separate coercion-site path, not yet handled — see CHECKPOINT-ERR.
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#import "modules/std.sx";
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E :: error { Neg }
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bare :: (cb: (s64) -> (s64, !E), n: s64) -> s64 { return cb(n) catch (e) -1; }
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chain :: (cb: Closure(s64) -> (s64, !E), n: s64) -> (s64, !E) { return try cb(n); }
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dbl :: (x: s64) -> (s64, !E) { if x < 0 { raise error.Neg; } return x * 2; }
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main :: () -> s32 {
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// failable closure literal through a bare fn-type param (matching ABI)
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print("bare ok={} err={}\n",
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bare(closure((x: s64) -> (s64, !E) { if x < 0 { raise error.Neg; } return x * 2; }), 5),
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bare(closure((x: s64) -> (s64, !E) => x * 2), -1)); // ok=10; err: arrow never raises → cb(-1) = -2
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// Closure(...) param, try-propagated, then caught at the call site
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print("chain ok={} err={}\n",
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chain(closure((x: s64) -> (s64, !E) => x + 6), 4) catch (e) 0, // 10
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chain(closure((x: s64) -> (s64, !E) { raise error.Neg; }), 1) catch (e) 0); // 0
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// NON-failable closure literal widened into the failable bare slot
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print("widen={}\n", bare(closure((x: s64) -> s64 => x + 1), 9)); // 10
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return 0;
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}
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