/*
[The "BSD licence"]
Copyright (c) 2005-2008 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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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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*/
package org.antlr.tool;
import org.antlr.analysis.*;
import org.antlr.misc.Utils;
import org.antlr.misc.IntervalSet;
import org.antlr.Tool;
import java.util.*;
import java.io.FileReader;
import java.io.BufferedReader;
/** Generate a random phrase given a grammar.
* Usage:
* java org.antlr.tool.RandomPhrase grammarFile.g startRule [seed]
*
* For example:
* java org.antlr.tool.RandomPhrase simple.g program 342
*
* The seed acts like a unique identifier so you can get the same random
* phrase back during unit testing, for example.
*
* If you do not specify a seed then the current time in milliseconds is used
* guaranteeing that you'll never see that seed again.
*
* NOTE: this does not work well for large grammars...it tends to recurse
* too much and build really long strings. I need throttle control; later.
*/
public class RandomPhrase {
public static final boolean debug = false;
protected static Random random;
/** an experimental method to generate random phrases for a given
* grammar given a start rule. Return a list of token types.
*/
protected static void randomPhrase(Grammar g, List<Integer> tokenTypes, String startRule) {
NFAState state = g.getRuleStartState(startRule);
NFAState stopState = g.getRuleStopState(startRule);
Stack ruleInvocationStack = new Stack();
while ( true ) {
if ( state==stopState && ruleInvocationStack.size()==0 ) {
break;
}
if ( debug ) System.out.println("state "+state);
if ( state.getNumberOfTransitions()==0 ) {
if ( debug ) System.out.println("dangling state: "+state);
return;
}
// end of rule node
if ( state.isAcceptState() ) {
NFAState invokingState = (NFAState)ruleInvocationStack.pop();
if ( debug ) System.out.println("pop invoking state "+invokingState);
//System.out.println("leave "+state.enclosingRule.name);
RuleClosureTransition invokingTransition =
(RuleClosureTransition)invokingState.transition[0];
// move to node after state that invoked this rule
state = invokingTransition.followState;
continue;
}
if ( state.getNumberOfTransitions()==1 ) {
// no branching, just take this path
Transition t0 = state.transition[0];
if ( t0 instanceof RuleClosureTransition ) {
ruleInvocationStack.push(state);
if ( debug ) System.out.println("push state "+state);
//System.out.println("call "+((RuleClosureTransition)t0).rule.name);
//System.out.println("stack depth="+ruleInvocationStack.size());
}
else if ( t0.label.isSet() || t0.label.isAtom() ) {
tokenTypes.add( getTokenType(t0.label) );
}
state = (NFAState)t0.target;
continue;
}
int decisionNumber = state.getDecisionNumber();
if ( decisionNumber==0 ) {
System.out.println("weird: no decision number but a choice node");
continue;
}
// decision point, pick ith alternative randomly
int n = g.getNumberOfAltsForDecisionNFA(state);
int randomAlt = random.nextInt(n) + 1;
if ( debug ) System.out.println("randomAlt="+randomAlt);
NFAState altStartState =
g.getNFAStateForAltOfDecision(state, randomAlt);
Transition t = altStartState.transition[0];
state = (NFAState)t.target;
}
}
protected static Integer getTokenType(Label label) {
if ( label.isSet() ) {
// pick random element of set
IntervalSet typeSet = (IntervalSet)label.getSet();
int randomIndex = random.nextInt(typeSet.size());
return typeSet.get(randomIndex);
}
else {
return Utils.integer(label.getAtom());
}
//System.out.println(t0.label.toString(g));
}
/** Used to generate random strings */
public static void main(String[] args) {
if ( args.length < 2 ) {
System.err.println("usage: java org.antlr.tool.RandomPhrase grammarfile startrule");
return;
}
String grammarFileName = args[0];
String startRule = args[1];
long seed = System.currentTimeMillis(); // use random seed unless spec.
if ( args.length==3 ) {
String seedStr = args[2];
seed = Long.parseLong(seedStr);
}
try {
random = new Random(seed);
CompositeGrammar composite = new CompositeGrammar();
Grammar parser = new Grammar(new Tool(), grammarFileName, composite);
composite.setDelegationRoot(parser);
FileReader fr = new FileReader(grammarFileName);
BufferedReader br = new BufferedReader(fr);
parser.parseAndBuildAST(br);
br.close();
parser.composite.assignTokenTypes();
parser.composite.defineGrammarSymbols();
parser.composite.createNFAs();
List leftRecursiveRules = parser.checkAllRulesForLeftRecursion();
if ( leftRecursiveRules.size()>0 ) {
return;
}
if ( parser.getRule(startRule)==null ) {
System.out.println("undefined start rule "+startRule);
return;
}
String lexerGrammarText = parser.getLexerGrammar();
Grammar lexer = new Grammar();
lexer.importTokenVocabulary(parser);
lexer.fileName = grammarFileName;
if ( lexerGrammarText!=null ) {
lexer.setGrammarContent(lexerGrammarText);
}
else {
System.err.println("no lexer grammar found in "+grammarFileName);
}
lexer.buildNFA();
leftRecursiveRules = lexer.checkAllRulesForLeftRecursion();
if ( leftRecursiveRules.size()>0 ) {
return;
}
//System.out.println("lexer:\n"+lexer);
List<Integer> tokenTypes = new ArrayList<Integer>(100);
randomPhrase(parser, tokenTypes, startRule);
System.out.println("token types="+tokenTypes);
for (int i = 0; i < tokenTypes.size(); i++) {
Integer ttypeI = (Integer) tokenTypes.get(i);
int ttype = ttypeI.intValue();
String ttypeDisplayName = parser.getTokenDisplayName(ttype);
if ( Character.isUpperCase(ttypeDisplayName.charAt(0)) ) {
List<Integer> charsInToken = new ArrayList<Integer>(10);
randomPhrase(lexer, charsInToken, ttypeDisplayName);
System.out.print(" ");
for (int j = 0; j < charsInToken.size(); j++) {
java.lang.Integer cI = (java.lang.Integer) charsInToken.get(j);
System.out.print((char)cI.intValue());
}
}
else { // it's a literal
String literal =
ttypeDisplayName.substring(1,ttypeDisplayName.length()-1);
System.out.print(" "+literal);
}
}
System.out.println();
}
catch (Error er) {
System.err.println("Error walking "+grammarFileName+" rule "+startRule+" seed "+seed);
er.printStackTrace(System.err);
}
catch (Exception e) {
System.err.println("Exception walking "+grammarFileName+" rule "+startRule+" seed "+seed);
e.printStackTrace(System.err);
}
}
}