Bike.Interpreter.Interpreter.Walk C# (CSharp) Метод

        public override object Walk(ForInStatement node)
        {
            var collection = node.Collection.Accept(this);
            if (collection == null)
                throw ErrorFactory.CreateNullError("Collection");
            if (!typeof(IEnumerable).IsAssignableFrom(collection.GetType()))
                throw ErrorFactory.CreateTypeError(string.Format("Object {0} is not enumerable", collection));

            string id;
            bool hasDeclaration = false;
            if (node.VariableDeclaration == null)
            {
                id = ((Identifier)node.LeftHandSideExpression.Accept(this)).Value;
            }
            else
            {
                id = node.VariableDeclaration.Identifier.Value;
                hasDeclaration = true;
            }

            object result = null;
            Action body = delegate
                              {
                                  foreach (var element in (IEnumerable)collection)
                                  {
                                      Context.CurrentFrame.Assign(id, element);
                                      try { result = node.Body.Accept(this); }
                                      catch (Break) { break; }
                                      catch (Next) { continue; }
                                  }
                              };
            Action<ScopeFrame> init = scopeFrame => scopeFrame.Define(id, null);
            Context.OpenScopeFor(body, withInit: init, when: hasDeclaration);
            return result;
        }