Implement string interpolation up to SSA.

dart/frog/leg/scanner/listener.dart

Index: dart/frog/leg/scanner/listener.dart
diff --git a/dart/frog/leg/scanner/listener.dart b/dart/frog/leg/scanner/listener.dart
index 3b9375a6b44bc27424afa973ba4d773deafdaa38..01e1342651c74623cd30cd7d1a8d0d044a1e9447 100644
--- a/dart/frog/leg/scanner/listener.dart
+++ b/dart/frog/leg/scanner/listener.dart
@@ -362,7 +362,7 @@ class Listener {
   void handleQualified(Token period) {
   }
 
-  void handleStringInterpolationPart(Token token) {
+  void handleStringInterpolationParts(int count) {
   }
 
   void handleSuperExpression(Token token) {
@@ -966,7 +966,8 @@ class NodeListener extends ElementListener {
 
   void endLiteralMapEntry(Token token) {
     Expression value = popNode();
-    LiteralString key = popNode();
+    // The key may be a LiteralString or a StringInterpolation.

[ngeoffray, 2011/12/20 11:54:45]

StringInterpolation should be rejected by someone though, right?

[ahe, 2011/12/20 13:19:24]

Yes. I looked at the specification. There is a bad test somewhere. Thinking
about it, I think I should use parseExpression() in parseMapLiteralEntry and
report an error if  key.asString() === null.

+    Expression key = popNode();
     // TODO(ahe): Create AST node.
     pushNode(new UnimplementedExpression('map entry', [key, value]));
   }
@@ -1036,11 +1037,19 @@ class NodeListener extends ElementListener {
     pushNode(new UnimplementedExpression('named argument', [name, argument]));
   }
 
-  void handleStringInterpolationPart(Token token) {
-    LiteralString string = popNode();
-    Expression expression = popNode();
-    canceler.cancel('string interpolation is not implemented',
-                    node: expression);
+  void handleStringInterpolationParts(int count) {
+    Link<StringInterpolationPart> parts =
+      const EmptyLink<StringInterpolationPart>();
+    for (int i = 0; i < count; i++) {
+      LiteralString string = popNode();
+      Expression expression = popNode();
+      parts = parts.prepend(new StringInterpolationPart(expression, string));
+    }
+    if (!parts.isEmpty()) {
+      LiteralString string = popNode();
+      NodeList nodes = new NodeList(null, parts, null, null);
+      pushNode(new StringInterpolation(string, nodes));
+    }
   }
 
   void endOptionalFormalParameters(int count,