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).
40 lines
1.7 KiB
Plaintext
40 lines
1.7 KiB
Plaintext
// Failable `or` chains (ERR step E2.4b). `lhs or rhs` with failable operands
|
|
// is a left-to-right, short-circuit chain: each failing attempt routes to the
|
|
// next operand; the chain resolves when an operand succeeds (or a value
|
|
// terminator absorbs). `try` marks an operand whose failure is visible routing
|
|
// (path-marker rule); a bare failable operand is allowed when a downstream
|
|
// terminator absorbs it. A `catch` over a parenthesized chain redirects the
|
|
// chain's total failure to the handler instead of the function. Absorbed
|
|
// failures clear the trace buffer; `onfail` does not fire for a failure that
|
|
// never leaves its block. This run takes only absorbed paths → exit 120.
|
|
|
|
#import "modules/std.sx";
|
|
|
|
E :: error { A, B };
|
|
|
|
fa :: (n: s32) -> (s32, !E) {
|
|
if n == 0 { raise error.A; }
|
|
if n < 0 { raise error.B; }
|
|
return n;
|
|
}
|
|
|
|
fv :: (n: s32) -> !E { // void (pure) failable
|
|
if n == 0 { raise error.A; }
|
|
return;
|
|
}
|
|
|
|
main :: () -> (s32, !E) {
|
|
onfail print("onfail fired (BUG)\n"); // must NOT fire — every chain below absorbs
|
|
|
|
r : s32 = 0;
|
|
r = r + (try fa(0) or try fa(7)); // a fails → b succeeds → 7
|
|
r = r + (try fa(0) or try fa(0) or try fa(3)); // first two fail → third → +3 = 10
|
|
r = r + (fa(0) or fa(0) or 96); // bare chain + value terminator → +96 = 106
|
|
r = r + ((try fa(0) or try fa(0)) catch (e) 5); // both fail → catch handler → +5 = 111
|
|
r = r + ((try fa(0) or try fa(9)) catch (e) 0); // second succeeds → catch skipped → +9 = 120
|
|
|
|
try fv(0) or try fv(1); // void chain: first fails → second succeeds
|
|
|
|
return r; // success → exit 120; onfail skipped
|
|
}
|