Support symbol literals.

sdk/lib/_internal/compiler/implementation/tree/nodes.dart

Index: sdk/lib/_internal/compiler/implementation/tree/nodes.dart
diff --git a/sdk/lib/_internal/compiler/implementation/tree/nodes.dart b/sdk/lib/_internal/compiler/implementation/tree/nodes.dart
index 210ebe52563b6e17541b614e1c3b0ff8372c1f57..7fc23a459ce4e0e5de7c5be6a1eee5d9ecfb52b7 100644
--- a/sdk/lib/_internal/compiler/implementation/tree/nodes.dart
+++ b/sdk/lib/_internal/compiler/implementation/tree/nodes.dart
@@ -76,6 +76,7 @@ abstract class Visitor<R> {
   }
   R visitSwitchCase(SwitchCase node) => visitNode(node);
   R visitSwitchStatement(SwitchStatement node) => visitStatement(node);
+  R visitSymbolLiteral(SymbolLiteral node) => visitExpression(node);
   R visitThrow(Throw node) => visitExpression(node);
   R visitTryStatement(TryStatement node) => visitStatement(node);
   R visitTypeAnnotation(TypeAnnotation node) => visitNode(node);
@@ -947,6 +948,39 @@ class LiteralList extends Expression {
   Token getEndToken() => elements.getEndToken();
 }
 
+class SymbolLiteral extends Expression {

[ahe, 2013/08/06 12:20:55]

This should be LiteralSymbol and it probably should extend Literal<Symbol>.

[Johnni Winther, 2013/09/03 12:27:50]

Changed to LiteralSymbol. Don't think it should extend Literal<Symbol>. The only
use case is in the SsaBuilder, where it needs to be generated as a constructed
constant anyway.

+  final Token hashToken;
+  final Operator operator;
+  final NodeList identifiers;

[ahe, 2013/08/06 12:20:55]

Feels to me like the natural way to represent this is with just a NodeList where
the last element might be an operator.

[Johnni Winther, 2013/09/03 12:27:50]

Done.

+
+  SymbolLiteral(this.hashToken, this.operator, this.identifiers);
+
+  SymbolLiteral asSymbolLiteral() => this;
+
+  void visitChildren(Visitor visitor) {
+    if (operator != null) operator.accept(visitor);
+    if (identifiers != null) identifiers.accept(visitor);
+  }
+
+  accept(Visitor visitor) => visitor.visitSymbolLiteral(this);
+
+  Token getBeginToken() => hashToken;
+  
+  Token getEndToken() {
+    if (operator != null) return operator.getEndToken();
+    return identifiers.getEndToken();
+  }
+  
+  String get nameString {
+    if (operator != null) {
+      return '${operator}';
+    } else {
+      return '${identifiers}';
+    }
+  }
+}
+
+
 class Identifier extends Expression {
   final Token token;