rust/src/test/run-pass/nullary-or-pattern.rs

tag blah { a; b; }

fn or_alt(q: blah) -> int {
  alt q { a. | b. { 42 } }
}

fn main() {
    assert (or_alt(a) == 42);
    assert (or_alt(b) == 42);
}
Allow omission of the '.' after nullary tag patterns This commit allows patterns like: alt x { some(_) { ... } none { } } without the '.' after none. The parser suspends judgment about whether a bare ident is a tag or a new bound variable; instead, the resolver disambiguates. This means that any code after resolution that pattern-matches on patterns needs to call pat_util::normalize_pat, which consults an environment to do this disambiguation. In addition, local variables are no longer allowed to shadow tag names, so this required changing some code (e.g. renaming variables named "mut", and renaming ast::sub to subtract). The parser currently accepts patterns with and without the '.'. Once the compiler and libraries are changed, it will no longer accept the '.'. 2012-01-14 18:05:07 -06:00			`tag blah { a; b; }`

			`fn or_alt(q: blah) -> int {`
			`alt q { a. \| b. { 42 } }`
			`}`

			`fn main() {`
			`assert (or_alt(a) == 42);`
			`assert (or_alt(b) == 42);`
			`}`