From 7c2979e26f23739b62fcda7500d4c5eac092c42c Mon Sep 17 00:00:00 2001
From: Lindsey Kuper <lkuper@mozilla.com>
Date: Fri, 6 May 2011 17:08:41 -0700
Subject: [PATCH] Starting on support for anonymous objects.  Just syntax so
 far.

---
 src/comp/front/ast.rs                  | 20 +++++++++++
 src/comp/front/parser.rs               | 50 ++++++++++++++++++++++++++
 src/test/run-pass/method-overriding.rs | 26 ++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 src/test/run-pass/method-overriding.rs

diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index 5e5185bf7ee..51977b5f7fb 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -296,6 +296,7 @@ tag expr_ {
     expr_check(@expr, ann);
     expr_port(ann);
     expr_chan(@expr, ann);
+    expr_anon_obj(anon_obj, vec[ty_param], obj_def_ids, ann);
 }
 
 type lit = spanned[lit_];
@@ -371,6 +372,25 @@ type _obj = rec(vec[obj_field] fields,
                 vec[@method] methods,
                 option::t[@method] dtor);
 
+
+// Hmm.  An anon_obj might extend an existing object, in which case it'll
+// probably add fields and methods.
+type anon_obj = rec(option.t[vec[obj_field]] fields,
+                    vec[@method] methods,
+                    option.t[ident] with_obj);
+
+tag mod_index_entry {
+    mie_view_item(@view_item);
+    mie_item(@item);
+    mie_tag_variant(@item /* tag item */, uint /* variant index */);
+}
+
+tag native_mod_index_entry {
+    nmie_view_item(@view_item);
+    nmie_item(@native_item);
+}
+
+type mod_index = hashmap[ident,mod_index_entry];
 type _mod = rec(vec[@view_item] view_items,
                 vec[@item] items);
 
diff --git a/src/comp/front/parser.rs b/src/comp/front/parser.rs
index 520090a52c7..f395ea16f3d 100644
--- a/src/comp/front/parser.rs
+++ b/src/comp/front/parser.rs
@@ -799,6 +799,56 @@ fn parse_bottom_expr(parser p) -> @ast::expr {
         }
 
         ex = ast::expr_rec(fields, base, p.get_ann());
+    }
+    // Anonymous object
+    else if (eat_word(p, "obj")) {
+
+        // FIXME: Can anonymous objects have ty params?
+        auto ty_params = parse_ty_params(p);
+
+        // Only make people type () if they're actually adding new fields
+        let option.t[vec[ast.obj_field]] fields = none[vec[ast.obj_field]];
+        if (p.peek() == token.LPAREN) {
+            auto pf = parse_obj_field;
+            hi = p.get_hi_pos();
+            expect(p, token.LPAREN);
+            fields = some[vec[ast.obj_field]]
+                (parse_seq_to_end[ast.obj_field] 
+                 (token.RPAREN,
+                  some(token.COMMA),
+                  pf, hi, p));
+        }
+
+        let vec[@ast.method] meths = vec();
+        let option.t[ast.ident] with_obj = none[ast.ident];
+
+        expect(p, token.LBRACE);
+        while (p.peek() != token.RBRACE) {
+            alt (p.peek()) {
+                case (token.WITH) { 
+                    with_obj = some[ast.ident](parse_ident(p));
+                }
+                case (_) {
+                    // fall through
+                }
+            }
+        }
+        hi = p.get_hi_pos();
+        expect(p, token.RBRACE);
+
+        // fields and methods may be *additional* or *overriding* fields
+        // and methods if there's a with_obj, or they may be the *only*
+        // fields and methods if there's no with_obj.
+
+        // We don't need to pull ".node" out of fields because it's not a
+        // "spanned".
+        let ast.anon_obj ob = rec(fields=fields,
+                                  methods=meths,
+                                  with_obj=with_obj);
+
+        auto odid = rec(ty=p.next_def_id(), ctor=p.next_def_id());
+
+        ex = ast.expr_anon_obj(ob, ty_params, odid, ast.ann_none);
     } else if (eat_word(p, "bind")) {
         auto e = parse_expr_res(p, RESTRICT_NO_CALL_EXPRS);
         fn parse_expr_opt(parser p) -> option::t[@ast::expr] {
diff --git a/src/test/run-pass/method-overriding.rs b/src/test/run-pass/method-overriding.rs
new file mode 100644
index 00000000000..bf68ddd1e42
--- /dev/null
+++ b/src/test/run-pass/method-overriding.rs
@@ -0,0 +1,26 @@
+// xfail-boot
+// xfail-stage0
+use std;
+import std._vec.len;
+fn main() {
+
+    obj a() {
+        fn foo() -> int {
+            ret 2;
+        }
+        fn bar() -> int {
+            ret self.foo();
+        }
+    }
+
+    auto my_a = a();
+
+    // Step 1 is to add support for this "with" syntax
+    auto my_b = obj { 
+        fn baz() -> int { 
+            ret self.foo(); 
+        } 
+        with my_a 
+    };
+    
+}