bjoernager/rust
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Allow binding of nested patterns

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See src/test/run-pass/nested-patterns.rs for some examples. The syntax is

    boundvar@subpattern

Which will match the subpattern as usual, but also bind boundvar to the
whole matched value.

Closes #838
This commit is contained in:
Marijn Haverbeke 2011-12-08 11:56:16 +01:00
parent 8c966b7b18
commit 9a269a3aa8
17 changed files with 132 additions and 79 deletions
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5
src/comp/syntax/ast_util.rs
View file

@ -58,7 +58,7 @@ type pat_id_map = std::map::hashmap<str, node_id>;
fn pat_id_map(pat: @pat) -> pat_id_map {
let map = std::map::new_str_hash::<node_id>();
pat_bindings(pat) {|bound|
let name = alt bound.node { pat_bind(n) { n } };
let name = alt bound.node { pat_bind(n, _) { n } };
map.insert(name, bound.id);
};
ret map;
@ -67,7 +67,8 @@ fn pat_id_map(pat: @pat) -> pat_id_map {
// FIXME: could return a constrained type
fn pat_bindings(pat: @pat, it: block(@pat)) {
alt pat.node {
pat_bind(_) { it(pat); }
pat_bind(_, option::none.) { it(pat); }
pat_bind(_, option::some(sub)) { it(pat); pat_bindings(sub, it); }
pat_tag(_, sub) { for p in sub { pat_bindings(p, it); } }
pat_rec(fields, _) { for f in fields { pat_bindings(f.pat, it); } }
pat_tup(elts) { for elt in elts { pat_bindings(elt, it); } }