1 /* 2 * [The "BSD license"] 3 * Copyright (c) 2010 Terence Parr 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 package org.antlr.test; 29 30 import org.antlr.analysis.DFA; 31 import org.antlr.analysis.NFA; 32 import org.antlr.runtime.ANTLRStringStream; 33 import org.antlr.tool.Grammar; 34 import org.junit.Test; 35 36 public class TestDFAMatching extends BaseTest { 37 38 /** Public default constructor used by TestRig */ 39 public TestDFAMatching() { 40 } 41 42 @Test public void testSimpleAltCharTest() throws Exception { 43 Grammar g = new Grammar( 44 "lexer grammar t;\n"+ 45 "A : {;}'a' | 'b' | 'c';"); 46 g.buildNFA(); 47 g.createLookaheadDFAs(false); 48 DFA dfa = g.getLookaheadDFA(1); 49 checkPrediction(dfa,"a",1); 50 checkPrediction(dfa,"b",2); 51 checkPrediction(dfa,"c",3); 52 checkPrediction(dfa,"d", NFA.INVALID_ALT_NUMBER); 53 } 54 55 @Test public void testSets() throws Exception { 56 Grammar g = new Grammar( 57 "lexer grammar t;\n"+ 58 "A : {;}'a'..'z' | ';' | '0'..'9' ;"); 59 g.buildNFA(); 60 g.createLookaheadDFAs(false); 61 DFA dfa = g.getLookaheadDFA(1); 62 checkPrediction(dfa,"a",1); 63 checkPrediction(dfa,"q",1); 64 checkPrediction(dfa,"z",1); 65 checkPrediction(dfa,";",2); 66 checkPrediction(dfa,"9",3); 67 } 68 69 @Test public void testFiniteCommonLeftPrefixes() throws Exception { 70 Grammar g = new Grammar( 71 "lexer grammar t;\n"+ 72 "A : 'a' 'b' | 'a' 'c' | 'd' 'e' ;"); 73 g.buildNFA(); 74 g.createLookaheadDFAs(false); 75 DFA dfa = g.getLookaheadDFA(1); 76 checkPrediction(dfa,"ab",1); 77 checkPrediction(dfa,"ac",2); 78 checkPrediction(dfa,"de",3); 79 checkPrediction(dfa,"q", NFA.INVALID_ALT_NUMBER); 80 } 81 82 @Test public void testSimpleLoops() throws Exception { 83 Grammar g = new Grammar( 84 "lexer grammar t;\n"+ 85 "A : (DIGIT)+ '.' DIGIT | (DIGIT)+ ;\n" + 86 "fragment DIGIT : '0'..'9' ;\n"); 87 g.buildNFA(); 88 g.createLookaheadDFAs(false); 89 DFA dfa = g.getLookaheadDFA(3); 90 checkPrediction(dfa,"32",2); 91 checkPrediction(dfa,"999.2",1); 92 checkPrediction(dfa,".2", NFA.INVALID_ALT_NUMBER); 93 } 94 95 protected void checkPrediction(DFA dfa, String input, int expected) 96 throws Exception 97 { 98 ANTLRStringStream stream = new ANTLRStringStream(input); 99 assertEquals(dfa.predict(stream), expected); 100 } 101 102 } 103
