| /* |
| * Copyright (C) 2010 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.clearsilver.jsilver.syntax; |
| |
| import com.google.clearsilver.jsilver.syntax.analysis.DepthFirstAdapter; |
| import com.google.clearsilver.jsilver.syntax.node.ASequenceExpression; |
| import com.google.clearsilver.jsilver.syntax.node.PExpression; |
| |
| import java.util.LinkedList; |
| |
| /** |
| * Simple optimizer to simplify expression sequences which only have a single element. This |
| * optimization should be run as early as possible because it simplifies the syntax tree (and some |
| * later optimizations may rely on the simplified structure). |
| */ |
| public class SequenceOptimizer extends DepthFirstAdapter { |
| |
| /** |
| * Removes sequence expressions with only one element. |
| */ |
| @Override |
| public void caseASequenceExpression(ASequenceExpression originalNode) { |
| super.caseASequenceExpression(originalNode); |
| LinkedList<PExpression> args = originalNode.getArgs(); |
| if (args.size() == 1) { |
| originalNode.replaceBy(args.getFirst()); |
| } |
| } |
| } |