Files
sx/examples/1048-errors-cleanup-absorption.sx
agra 83ec2536af lang: catch/onfail error bindings take parens
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).
2026-06-10 23:05:02 +03:00

29 lines
1.0 KiB
Plaintext

// Failable calls in cleanup bodies must be absorbed locally (ERR step E1.7). A
// `defer` / `onfail` body runs while the block is already exiting, so a failable
// it calls has nowhere to propagate — it must be handled in place with `catch`
// or an `or <value>` terminator. This file shows the accepted forms; the bare
// (un-absorbed) form is rejected in 1049.
#import "modules/std.sx";
E :: error { Bad }
failing :: () -> !E { raise error.Bad; }
recover :: () -> (s32, !E) { raise error.Bad; }
work :: (n: s32) -> !E {
defer print("defer: always\n"); // plain cleanup
onfail { failing() catch (e) print("onfail: caught (catch)\n"); } // catch absorbs
onfail { x := recover() or 7; print("onfail: x={} (or)\n", x); } // or-value absorbs
if n < 0 { raise error.Bad; }
return;
}
main :: () -> s32 {
print("[error]\n");
a := work(-1); // raises → onfail bodies fire, then defer (reverse decl order)
print("[ok]\n");
b := work(2); // success → only defer fires
return 0;
}