rustc: Implement function types

src/comp/front/ast.rs

@@ -130,6 +130,7 @@ tag ty_ {
     ty_box(@ty);
     ty_vec(@ty);
     ty_tup(vec[tup(bool /* mutability */, @ty)]);
+    ty_fn(vec[rec(mode mode, @ty ty)], @ty);        // TODO: effect
     ty_path(path, option.t[def]);
 }
 

src/comp/front/parser.rs

@@ -108,6 +108,45 @@ impure fn parse_possibly_mutable_ty(parser p) -> tup(bool, @ast.ty) {
     ret tup(mut, parse_ty(p));
 }
 
+impure fn parse_ty_fn(parser p) -> ast.ty_ {
+    impure fn parse_fn_input_ty(parser p) -> rec(ast.mode mode, @ast.ty ty) {
+        auto mode;
+        if (p.peek() == token.BINOP(token.AND)) {
+            p.bump();
+            mode = ast.alias;
+        } else {
+            mode = ast.val;
+        }
+
+        auto t = parse_ty(p);
+
+        alt (p.peek()) {
+            case (token.IDENT(_)) { p.bump(); /* ignore the param name */ }
+            case (_) { /* no param name present */ }
+        }
+
+        ret rec(mode=mode, ty=t);
+    }
+
+    auto lo = p.get_span();
+
+    expect(p, token.FN);
+
+    auto f = parse_fn_input_ty; // FIXME: trans_const_lval bug
+    auto inputs = parse_seq[rec(ast.mode mode, @ast.ty ty)](token.LPAREN,
+        token.RPAREN, some(token.COMMA), f, p);
+
+    let @ast.ty output;
+    if (p.peek() == token.RARROW) {
+        p.bump();
+        output = parse_ty(p);
+    } else {
+        output = @spanned(lo, inputs.span, ast.ty_nil);
+    }
+
+    ret ast.ty_fn(inputs.node, output);
+}
+            
 impure fn parse_ty(parser p) -> @ast.ty {
     auto lo = p.get_span();
     let ast.ty_ t;
@@ -135,6 +174,10 @@ impure fn parse_ty(parser p) -> @ast.ty {
             t = ast.ty_tup(elems.node);
         }
 
+        case (token.FN) {
+            t = parse_ty_fn(p);
+        }
+
         case (_) {
             p.err("expecting type");
             t = ast.ty_nil;

src/comp/middle/fold.rs

@@ -46,8 +46,12 @@ type ast_fold[ENV] =
      (fn(&ENV e, &span sp,
          vec[tup(bool, @ty)] elts) -> @ty)        fold_ty_tup,
 
+     (fn(&ENV e, &span sp,
+         vec[rec(ast.mode mode, @ty ty)] inputs,
+         @ty output) -> @ty)                      fold_ty_fn,
+
      (fn(&ENV e, &span sp, ast.path p,
-         &option.t[def] d) -> @ty)                  fold_ty_path,
+         &option.t[def] d) -> @ty)                fold_ty_path,
 
      // Expr folds.
      (fn(&ENV e, &span sp,
@@ -226,6 +230,10 @@ fn fold_ty[ENV](&ENV env, ast_fold[ENV] fld, @ty t) -> @ty {
             }
             ret fld.fold_ty_path(env_, t.span, path, ref_opt);
         }
+
+        case (ast.ty_fn(?inputs, ?output)) {
+            ret fld.fold_ty_fn(env_, t.span, inputs, output);
+        }
     }
 }
 
@@ -567,6 +575,12 @@ fn identity_fold_ty_tup[ENV](&ENV env, &span sp, vec[tup(bool,@ty)] elts)
     ret @respan(sp, ast.ty_tup(elts));
 }
 
+fn identity_fold_ty_fn[ENV](&ENV env, &span sp,
+                            vec[rec(ast.mode mode, @ty ty)] inputs,
+                            @ty output) -> @ty {
+    ret @respan(sp, ast.ty_fn(inputs, output));
+}
+
 fn identity_fold_ty_path[ENV](&ENV env, &span sp, ast.path p,
                         &option.t[def] d) -> @ty {
     ret @respan(sp, ast.ty_path(p, d));
@@ -785,6 +799,7 @@ fn new_identity_fold[ENV]() -> ast_fold[ENV] {
          fold_ty_box     = bind identity_fold_ty_box[ENV](_,_,_),
          fold_ty_vec     = bind identity_fold_ty_vec[ENV](_,_,_),
          fold_ty_tup     = bind identity_fold_ty_tup[ENV](_,_,_),
+         fold_ty_fn      = bind identity_fold_ty_fn[ENV](_,_,_,_),
          fold_ty_path    = bind identity_fold_ty_path[ENV](_,_,_,_),
 
          fold_expr_vec    = bind identity_fold_expr_vec[ENV](_,_,_,_),