frog: use type annotation in map and list literals

frog/parser.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // TODO(jimhug): Error recovery needs major work!
 /**
  * A simple recursive descent parser for the dart language.
  *
  * This parser is designed to be more permissive than the official
  * Dart grammar.  It is expected that many grammar errors would be
@@ skipping 1433 matching lines @@
       }
     }
     return new MapExpression(isConst, type, items, _makeSpan(start));
   }
 
   finishTypedLiteral(int start, bool isConst) {
     var span = _makeSpan(start);
     var typeToBeNamedLater = new NameTypeReference(false, null, null, span);
     var genericType = addTypeArguments(typeToBeNamedLater, 0);
 
-    // TODO(jimhug): Fill in correct typeToBeNamedLater details...
     if (_peekKind(TokenKind.LBRACK) || _peekKind(TokenKind.INDEX)) {
+      genericType.baseType = new TypeReference(span, world.listType);
       return finishListLiteral(start, isConst, genericType);
     } else if (_peekKind(TokenKind.LBRACE)) {
+      genericType.baseType = new TypeReference(span, world.mapType);
+      if (genericType.typeArguments.length != 1) {

[Jennifer Messerly, 2011/12/08 02:13:26]

probably worth pulling "genericType.typeArguments" into a temp since it's used 5
times as an rvalue.

[Siggi Cherem (dart-lang), 2011/12/08 23:02:15]

Done.

+        _error('a map literal takes one type argument specfying the value type',

[Jennifer Messerly, 2011/12/08 02:13:26]

I hope we follow up with the spec here. This current rule doesn't seem very
future proofed. I can see either: 1. the Map type allows constant keys in
literals, or 2. other collections get literals and also need the <...> syntax,
but what if they need more than one type arg?

Maybe add a TODO here?

[Siggi Cherem (dart-lang), 2011/12/08 23:02:15]

Added TODO. Good news is that the spec actually has an explicit note to revisit
this.

+            genericType.typeArguments.length == 0
+              ? genericType.typeArguments.span
+              : genericType.typeArguments[1].span);
+      }
+      genericType.typeArguments = [new TypeReference(span, world.stringType),
+          genericType.typeArguments[0]];
       return finishMapLiteral(start, isConst, genericType);
     } else {
       _errorExpected('array or map literal');
     }
   }
 
   ///////////////////////////////////////////////////////////////////
   // Some auxilary productions.
   ///////////////////////////////////////////////////////////////////
   _readModifiers() {
@@ skipping 274 matching lines @@
   int _pos = 0;
   next() {
     var token = tokens[_pos];
     ++_pos;
     if (_pos == tokens.length) {
       parser.tokenizer = previousTokenizer;
     }
     return token;
   }
 }