libsyntax: Implement [int*3] syntax for fixed length vector types

Author: pcwalton

src/libsyntax/parse/parser.rs

@@ -472,7 +472,19 @@ class parser {
             ty_rec(elems)
         } else if self.token == token::LBRACKET {
             self.expect(token::LBRACKET);
-            let t = ty_vec(self.parse_mt());
+            let mut t = ty_vec(self.parse_mt());
+
+            // Parse the `* 3` in `[ int * 3 ]`
+            match self.maybe_parse_fixed_vstore_with_star() {
+                none => {}
+                some(suffix) => {
+                    t = ty_fixed_length(@{
+                        id: self.get_id(),
+                        node: t,
+                        span: mk_sp(lo, self.last_span.hi)
+                    }, suffix)
+                }
+            }
             self.expect(token::RBRACKET);
             t
         } else if self.token == token::BINOP(token::AND) {
@@ -609,6 +621,22 @@ class parser {
         }
     }
 
+    fn maybe_parse_fixed_vstore_with_star() -> option<option<uint>> {
+        if self.eat(token::BINOP(token::STAR)) {
+            match copy self.token {
+              token::UNDERSCORE => {
+                self.bump(); some(none)
+              }
+              token::LIT_INT_UNSUFFIXED(i) if i >= 0i64 => {
+                self.bump(); some(some(i as uint))
+              }
+              _ => none
+            }
+        } else {
+            none
+        }
+    }
+
     fn lit_from_token(tok: token::token) -> lit_ {
         match tok {
           token::LIT_INT(i, it) => lit_int(i, it),

src/test/run-pass/vec-fixed-length.rs

@@ -0,0 +1,5 @@
+fn main() {
+    let x: [int*4] = [1, 2, 3, 4];
+    io::println(fmt!("%d", x[0]));
+}
+