| /* |
| * [The "BSD license"] |
| * Copyright (c) 2010 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.test; |
| |
| import org.antlr.analysis.DFA; |
| import org.antlr.analysis.NFA; |
| import org.antlr.runtime.ANTLRStringStream; |
| import org.antlr.tool.Grammar; |
| import org.junit.Test; |
| |
| public class TestDFAMatching extends BaseTest { |
| |
| /** Public default constructor used by TestRig */ |
| public TestDFAMatching() { |
| } |
| |
| @Test public void testSimpleAltCharTest() throws Exception { |
| Grammar g = new Grammar( |
| "lexer grammar t;\n"+ |
| "A : {;}'a' | 'b' | 'c';"); |
| g.buildNFA(); |
| g.createLookaheadDFAs(false); |
| DFA dfa = g.getLookaheadDFA(1); |
| checkPrediction(dfa,"a",1); |
| checkPrediction(dfa,"b",2); |
| checkPrediction(dfa,"c",3); |
| checkPrediction(dfa,"d", NFA.INVALID_ALT_NUMBER); |
| } |
| |
| @Test public void testSets() throws Exception { |
| Grammar g = new Grammar( |
| "lexer grammar t;\n"+ |
| "A : {;}'a'..'z' | ';' | '0'..'9' ;"); |
| g.buildNFA(); |
| g.createLookaheadDFAs(false); |
| DFA dfa = g.getLookaheadDFA(1); |
| checkPrediction(dfa,"a",1); |
| checkPrediction(dfa,"q",1); |
| checkPrediction(dfa,"z",1); |
| checkPrediction(dfa,";",2); |
| checkPrediction(dfa,"9",3); |
| } |
| |
| @Test public void testFiniteCommonLeftPrefixes() throws Exception { |
| Grammar g = new Grammar( |
| "lexer grammar t;\n"+ |
| "A : 'a' 'b' | 'a' 'c' | 'd' 'e' ;"); |
| g.buildNFA(); |
| g.createLookaheadDFAs(false); |
| DFA dfa = g.getLookaheadDFA(1); |
| checkPrediction(dfa,"ab",1); |
| checkPrediction(dfa,"ac",2); |
| checkPrediction(dfa,"de",3); |
| checkPrediction(dfa,"q", NFA.INVALID_ALT_NUMBER); |
| } |
| |
| @Test public void testSimpleLoops() throws Exception { |
| Grammar g = new Grammar( |
| "lexer grammar t;\n"+ |
| "A : (DIGIT)+ '.' DIGIT | (DIGIT)+ ;\n" + |
| "fragment DIGIT : '0'..'9' ;\n"); |
| g.buildNFA(); |
| g.createLookaheadDFAs(false); |
| DFA dfa = g.getLookaheadDFA(3); |
| checkPrediction(dfa,"32",2); |
| checkPrediction(dfa,"999.2",1); |
| checkPrediction(dfa,".2", NFA.INVALID_ALT_NUMBER); |
| } |
| |
| protected void checkPrediction(DFA dfa, String input, int expected) |
| throws Exception |
| { |
| ANTLRStringStream stream = new ANTLRStringStream(input); |
| assertEquals(dfa.predict(stream), expected); |
| } |
| |
| } |