| /* |
| [The "BSD license"] |
| Copyright (c) 2005-2009 Terence Parr |
| All rights reserved. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions |
| are met: |
| 1. Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| 2. Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| 3. The name of the author may not be used to endorse or promote products |
| derived from this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| package org.antlr.runtime.debug; |
| |
| import org.antlr.runtime.IntStream; |
| import org.antlr.runtime.TokenStream; |
| |
| /** The default tracer mimics the traceParser behavior of ANTLR 2.x. |
| * This listens for debugging events from the parser and implies |
| * that you cannot debug and trace at the same time. |
| */ |
| public class Tracer extends BlankDebugEventListener { |
| public IntStream input; |
| protected int level = 0; |
| |
| public Tracer(IntStream input) { |
| this.input = input; |
| } |
| |
| public void enterRule(String ruleName) { |
| for (int i=1; i<=level; i++) {System.out.print(" ");} |
| System.out.println("> "+ruleName+" lookahead(1)="+getInputSymbol(1)); |
| level++; |
| } |
| |
| public void exitRule(String ruleName) { |
| level--; |
| for (int i=1; i<=level; i++) {System.out.print(" ");} |
| System.out.println("< "+ruleName+" lookahead(1)="+getInputSymbol(1)); |
| } |
| |
| public Object getInputSymbol(int k) { |
| if ( input instanceof TokenStream ) { |
| return ((TokenStream)input).LT(k); |
| } |
| return new Character((char)input.LA(k)); |
| } |
| } |
| |
| |