| /* |
| * Copyright 2008 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.gwt.dev.js; |
| |
| import com.google.gwt.dev.js.ast.JsBlock; |
| import com.google.gwt.dev.js.ast.JsBreak; |
| import com.google.gwt.dev.js.ast.JsContext; |
| import com.google.gwt.dev.js.ast.JsDebugger; |
| import com.google.gwt.dev.js.ast.JsDoWhile; |
| import com.google.gwt.dev.js.ast.JsEmpty; |
| import com.google.gwt.dev.js.ast.JsExprStmt; |
| import com.google.gwt.dev.js.ast.JsFor; |
| import com.google.gwt.dev.js.ast.JsForIn; |
| import com.google.gwt.dev.js.ast.JsIf; |
| import com.google.gwt.dev.js.ast.JsLabel; |
| import com.google.gwt.dev.js.ast.JsReturn; |
| import com.google.gwt.dev.js.ast.JsStatement; |
| import com.google.gwt.dev.js.ast.JsSwitch; |
| import com.google.gwt.dev.js.ast.JsThrow; |
| import com.google.gwt.dev.js.ast.JsTry; |
| import com.google.gwt.dev.js.ast.JsVars; |
| import com.google.gwt.dev.js.ast.JsVisitor; |
| import com.google.gwt.dev.js.ast.JsWhile; |
| |
| /** |
| * Determines if a statement at the end of a block requires a semicolon. |
| * |
| * For example, the following statements require semicolons:<br> |
| * <ul> |
| * <li>if (cond);</li> |
| * <li>while (cond);</li> |
| * </ul> |
| * |
| * The following do not require semicolons:<br> |
| * <ul> |
| * <li>return 1</li> |
| * <li>do {} while(true)</li> |
| * </ul> |
| */ |
| public class JsRequiresSemiVisitor extends JsVisitor { |
| |
| public static boolean exec(JsStatement lastStatement) { |
| JsRequiresSemiVisitor visitor = new JsRequiresSemiVisitor(); |
| visitor.accept(lastStatement); |
| return visitor.needsSemicolon; |
| } |
| |
| private boolean needsSemicolon = false; |
| |
| private JsRequiresSemiVisitor() { |
| } |
| |
| @Override |
| public boolean visit(JsBlock x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsBreak x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsDebugger x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsDoWhile x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsEmpty x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsExprStmt x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsFor x, JsContext ctx) { |
| if (x.getBody() instanceof JsEmpty) { |
| needsSemicolon = true; |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsForIn x, JsContext ctx) { |
| if (x.getBody() instanceof JsEmpty) { |
| needsSemicolon = true; |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsIf x, JsContext ctx) { |
| JsStatement thenStmt = x.getThenStmt(); |
| JsStatement elseStmt = x.getElseStmt(); |
| JsStatement toCheck = thenStmt; |
| if (elseStmt != null) { |
| toCheck = elseStmt; |
| } |
| if (toCheck instanceof JsEmpty) { |
| needsSemicolon = true; |
| } else { |
| // Must recurse to determine last statement (possible if-else chain). |
| accept(toCheck); |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsLabel x, JsContext ctx) { |
| if (x.getStmt() instanceof JsEmpty) { |
| needsSemicolon = true; |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsReturn x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsSwitch x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsThrow x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsTry x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsVars x, JsContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public boolean visit(JsWhile x, JsContext ctx) { |
| if (x.getBody() instanceof JsEmpty) { |
| needsSemicolon = true; |
| } |
| return false; |
| } |
| |
| } |