Teach AST, parser, folder about iter items.

Author: graydon

src/comp/front/ast.rs

@@ -200,6 +200,7 @@ tag ty_ {
 
 type arg = rec(mode mode, @ty ty, ident ident, def_id id);
 type _fn = rec(effect effect,
+               bool is_iter,
                vec[arg] inputs,
                @ty output,
                block body);

src/comp/front/parser.rs

@@ -1403,7 +1403,7 @@ impure fn parse_ty_params(parser p) -> vec[ast.ty_param] {
     ret ty_params;
 }
 
-impure fn parse_fn(parser p, ast.effect eff) -> ast._fn {
+impure fn parse_fn(parser p, ast.effect eff, bool is_iter) -> ast._fn {
     auto pf = parse_arg;
     let util.common.spanned[vec[ast.arg]] inputs =
         // FIXME: passing parse_arg as an lval doesn't work at the
@@ -1425,18 +1425,25 @@ impure fn parse_fn(parser p, ast.effect eff) -> ast._fn {
     auto body = parse_block(p);
 
     ret rec(effect = eff,
+            is_iter = is_iter,
             inputs = inputs.node,
             output = output,
             body = body);
 }
 
-impure fn parse_item_fn(parser p, ast.effect eff) -> @ast.item {
+impure fn parse_item_fn_or_iter(parser p, ast.effect eff,
+                                bool is_iter) -> @ast.item {
     auto lo = p.get_span();
-    expect(p, token.FN);
+    if (is_iter) {
+        expect(p, token.ITER);
+    } else {
+        expect(p, token.FN);
+    }
     auto id = parse_ident(p);
     auto ty_params = parse_ty_params(p);
-    auto f = parse_fn(p, eff);
-    auto item = ast.item_fn(id, f, ty_params, p.next_def_id(), ast.ann_none);
+    auto f = parse_fn(p, eff, is_iter);
+    auto item = ast.item_fn(id, f, ty_params,
+                            p.next_def_id(), ast.ann_none);
     ret @spanned(lo, f.body.span, item);
 }
 
@@ -1450,9 +1457,14 @@ impure fn parse_obj_field(parser p) -> ast.obj_field {
 impure fn parse_method(parser p) -> @ast.method {
     auto lo = p.get_span();
     auto eff = parse_effect(p);
-    expect(p, token.FN);
+    auto is_iter = false;
+    alt (p.peek()) {
+        case (token.FN) { p.bump(); }
+        case (token.ITER) { p.bump(); is_iter = true; }
+        case (?t) { unexpected(p, t); }
+    }
     auto ident = parse_ident(p);
-    auto f = parse_fn(p, eff);
+    auto f = parse_fn(p, eff, is_iter);
     auto meth = rec(ident=ident, meth=f,
                     id=p.next_def_id(), ann=ast.ann_none);
     ret @spanned(lo, f.body.span, meth);
@@ -1655,7 +1667,11 @@ impure fn parse_item(parser p) -> @ast.item {
 
         case (token.FN) {
             check (lyr == ast.layer_value);
-            ret parse_item_fn(p, eff);
+            ret parse_item_fn_or_iter(p, eff, false);
+        }
+        case (token.ITER) {
+            check (lyr == ast.layer_value);
+            ret parse_item_fn_or_iter(p, eff, true);
         }
         case (token.MOD) {
             check (eff == ast.eff_pure);

src/comp/middle/fold.rs

@@ -221,6 +221,7 @@ type ast_fold[ENV] =
          &ast.block_) -> block)                   fold_block,
 
      (fn(&ENV e, ast.effect effect,
+         bool is_iter,
          vec[arg] inputs,
          @ty output, &block body) -> ast._fn)     fold_fn,
 
@@ -671,7 +672,7 @@ fn fold_fn[ENV](&ENV env, ast_fold[ENV] fld, &ast._fn f) -> ast._fn {
     auto output = fold_ty[ENV](env, fld, f.output);
     auto body = fold_block[ENV](env, fld, f.body);
 
-    ret fld.fold_fn(env, f.effect, inputs, output, body);
+    ret fld.fold_fn(env, f.effect, f.is_iter, inputs, output, body);
 }
 
 
@@ -1129,10 +1130,12 @@ fn identity_fold_block[ENV](&ENV e, &span sp, &ast.block_ blk) -> block {
 
 fn identity_fold_fn[ENV](&ENV e,
                          ast.effect effect,
+                         bool is_iter,
                          vec[arg] inputs,
                          @ast.ty output,
                          &block body) -> ast._fn {
-    ret rec(effect=effect, inputs=inputs, output=output, body=body);
+    ret rec(effect=effect, is_iter=is_iter, inputs=inputs,
+            output=output, body=body);
 }
 
 fn identity_fold_mod[ENV](&ENV e, &ast._mod m) -> ast._mod {
@@ -1271,7 +1274,7 @@ fn new_identity_fold[ENV]() -> ast_fold[ENV] {
              bind identity_fold_view_item_import[ENV](_,_,_,_,_),
 
          fold_block = bind identity_fold_block[ENV](_,_,_),
-         fold_fn = bind identity_fold_fn[ENV](_,_,_,_,_),
+         fold_fn = bind identity_fold_fn[ENV](_,_,_,_,_,_),
          fold_mod = bind identity_fold_mod[ENV](_,_),
          fold_crate = bind identity_fold_crate[ENV](_,_,_),
          fold_obj = bind identity_fold_obj[ENV](_,_,_),

src/comp/middle/typeck.rs

@@ -1590,7 +1590,7 @@ fn check_const(&@crate_ctxt ccx, &span sp, ast.ident ident, @ast.ty t,
 }
 
 fn check_fn(&@crate_ctxt ccx, ast.effect effect,
-            vec[ast.arg] inputs,
+            bool is_iter, vec[ast.arg] inputs,
             @ast.ty output, &ast.block body) -> ast._fn {
     auto local_ty_table = @common.new_def_hash[@ty.t]();
 
@@ -1618,8 +1618,8 @@ fn check_fn(&@crate_ctxt ccx, ast.effect effect,
     auto block_t = check_block(fcx, body);
     auto block_wb = writeback(fcx, block_t);
 
-    auto fn_t = rec(effect=effect, inputs=inputs, output=output,
-                    body=block_wb);
+    auto fn_t = rec(effect=effect, is_iter=is_iter,
+                    inputs=inputs, output=output, body=block_wb);
     ret fn_t;
 }
 
@@ -1670,7 +1670,7 @@ fn check_crate(session.session sess, @ast.crate crate) -> @ast.crate {
     auto fld = fold.new_identity_fold[@crate_ctxt]();
 
     fld = @rec(update_env_for_item = bind update_obj_fields(_, _),
-               fold_fn      = bind check_fn(_,_,_,_,_),
+               fold_fn      = bind check_fn(_,_,_,_,_,_),
                fold_item_fn = bind check_item_fn(_,_,_,_,_,_,_)
                with *fld);
     ret fold.fold_crate[@crate_ctxt](ccx, fld, result._0);