/*
[The "BSD licence"]
Copyright (c) 2005-2006 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
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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,
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*/
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.Before;
import org.junit.Ignore;
import org.junit.Test;
import static org.junit.Assert.*;
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);
}
}