Support for stack traces in catch blocks.

frog/leg/tree/nodes.dart

Index: frog/leg/tree/nodes.dart
===================================================================
--- frog/leg/tree/nodes.dart	(revision 5017)
+++ frog/leg/tree/nodes.dart	(working copy)
@@ -1660,6 +1660,20 @@
 
   accept(Visitor visitor) => visitor.visitCatchBlock(this);
 
+  Node get exception() {
+    if (formals.nodes.isEmpty()) return null;

[ahe, 2012/03/06 12:24:07]

Perhaps you should check if this returns null in the resolver.

[ngeoffray, 2012/03/06 12:29:40]

It's already doing it.

+    VariableDefinitions declarations = formals.nodes.head;
+    return declarations.definitions.nodes.head;
+  }
+
+  Node get trace() {
+    if (formals.nodes.isEmpty()) return null;
+    Link<VariableDefinitions> declarations = formals.nodes.tail;
+    return declarations.isEmpty()
+        ? null
+        : declarations.head.definitions.nodes.head;
+  }
+
   visitChildren(Visitor visitor) {
     formals.accept(visitor);
     block.accept(visitor);