Refactor of PolymerExpressions. Adds "as" expressions.

pkg/polymer_expressions/lib/eval.dart

Index: pkg/polymer_expressions/lib/eval.dart
diff --git a/pkg/polymer_expressions/lib/eval.dart b/pkg/polymer_expressions/lib/eval.dart
index be2fdec6245a73779b9a518331d8852be6c583db..8c3305a9cbbfbc08706b57d78b99c25ffc72f4d6 100644
--- a/pkg/polymer_expressions/lib/eval.dart
+++ b/pkg/polymer_expressions/lib/eval.dart
@@ -215,21 +215,6 @@ class Scope {
     }
   }
 
-  bool contains(String name) {
-    if (_variables.containsKey(name)) {
-      return true;
-    } else {
-      var symbol = new Symbol(name);
-      var classMirror = _modelMirror.type;
-      if (getMemberMirror(classMirror, symbol) != null) {
-        return true;
-      }
-    }
-    if (parent != null) {
-      return parent.contains(name);
-    }
-    return false;
-  }
 }
 
 Object _convert(v) {
@@ -290,11 +275,6 @@ class Updater extends RecursiveVisitor {
   visitExpression(ExpressionObserver e) {
     e._observe(scope);
   }
-
-  visitInExpression(InObserver c) {
-    visit(c.right);
-    visitExpression(c);
-  }
 }
 
 class ObserverBuilder extends Visitor {
@@ -389,14 +369,13 @@ class ObserverBuilder extends Visitor {
   }
 
   visitInExpression(InExpression i) {
-    // don't visit the left. It's an identifier, but we don't want to evaluate
-    // it, we just want to add it to the comprehension object
-    var left = visit(i.left);
-    var right = visit(i.right);
-    var inexpr = new InObserver(i, left, right);
-    right._parent = inexpr;
-    return inexpr;
+    throw "can't eval an in expression";

[Jennifer Messerly, 2014/01/31 02:48:50]

throw new UnsupportedError?

[justinfagnani, 2014/03/12 23:21:30]

Done.

+  }
+
+  visitAsExpression(AsExpression i) {
+    throw "can't eval an as expression";
   }
+
 }
 
 class EmptyObserver extends ExpressionObserver<EmptyExpression>
@@ -676,32 +655,6 @@ class InvokeObserver extends ExpressionObserver<Invoke> implements Invoke {
   accept(Visitor v) => v.visitInvoke(this);
 }
 
-class InObserver extends ExpressionObserver<InExpression>
-    implements InExpression {
-  IdentifierObserver left;
-  ExpressionObserver right;
-
-  InObserver(Expression expr, this.left, this.right) : super(expr);
-
-  _updateSelf(Scope scope) {
-    Identifier identifier = left;
-    var iterable = right._value;
-
-    if (iterable is! Iterable && iterable != null) {
-      throw new EvalException("right side of 'in' is not an iterator");
-    }
-
-    if (iterable is ObservableList) {
-      _subscription = iterable.listChanges.listen((_) => _invalidate(scope));
-    }
-
-    // TODO: make Comprehension observable and update it
-    _value = new Comprehension(identifier.value, iterable);
-  }
-
-  accept(Visitor v) => v.visitInExpression(this);
-}
-
 _toBool(v) => (v == null) ? false : v;
 
 /** Call a [Function] or a [Method]. */
@@ -718,19 +671,6 @@ Object call(Object receiver, List args) {
   return _convert(result);
 }
 
-/**
- * A comprehension declaration ("a in b"). [identifier] is the loop variable
- * that's added to the scope during iteration. [iterable] is the set of
- * objects to iterate over.
- */
-class Comprehension {
-  final String identifier;
-  final Iterable iterable;
-
-  Comprehension(this.identifier, Iterable iterable)
-      : iterable = (iterable != null) ? iterable : const [];
-}
-
 /** A method on a model object in a [Scope]. */
 class Method {
   final InstanceMirror mirror;