tool/src/main/java/org/antlr/tool/Interp.java

/*
 * [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.tool;

import org.antlr.Tool;
import org.antlr.runtime.*;
import org.antlr.runtime.tree.ParseTree;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.StringTokenizer;

/** Interpret any ANTLR grammar:
 *
 *  java Interp file.g tokens-to-ignore start-rule input-file
 *
 *  java Interp C.g 'WS COMMENT' program t.c
 *
 *  where the WS and COMMENT are the names of tokens you want to have
 *  the parser ignore.
 */
public class Interp {
    public static class FilteringTokenStream extends CommonTokenStream {
        public FilteringTokenStream(TokenSource src) { super(src); }
        Set<Integer> hide = new HashSet<Integer>();
        protected void sync(int i) {
            super.sync(i);
            if ( hide.contains(get(i).getType()) ) get(i).setChannel(Token.HIDDEN_CHANNEL);
        }
        public void setTokenTypeChannel(int ttype, int channel) {
            hide.add(ttype);
        }
    }

	// pass me a java file to parse
	public static void main(String[] args) throws Exception {
		if ( args.length!=4 ) {
			System.err.println("java Interp file.g tokens-to-ignore start-rule input-file");
			return;
		}
		String grammarFileName = args[0];
		String ignoreTokens = args[1];
		String startRule = args[2];
		String inputFileName = args[3];

		// TODO: using wrong constructor now
		Tool tool = new Tool();
		CompositeGrammar composite = new CompositeGrammar();
		Grammar parser = new Grammar(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(tool);
		lexer.importTokenVocabulary(parser);
		lexer.fileName = grammarFileName;
		lexer.setTool(tool);
		if ( lexerGrammarText!=null ) {
			lexer.setGrammarContent(lexerGrammarText);
		}
		else {
			System.err.println("no lexer grammar found in "+grammarFileName);
		}
		lexer.composite.createNFAs();
		
		CharStream input =
			new ANTLRFileStream(inputFileName);
		Interpreter lexEngine = new Interpreter(lexer, input);
		FilteringTokenStream tokens = new FilteringTokenStream(lexEngine);
		StringTokenizer tk = new StringTokenizer(ignoreTokens, " ");
		while ( tk.hasMoreTokens() ) {
			String tokenName = tk.nextToken();
			tokens.setTokenTypeChannel(lexer.getTokenType(tokenName), 99);
		}

		if ( parser.getRule(startRule)==null ) {
			System.err.println("Rule "+startRule+" does not exist in "+grammarFileName);
			return;
		}
		Interpreter parseEngine = new Interpreter(parser, tokens);
		ParseTree t = parseEngine.parse(startRule);
		System.out.println(t.toStringTree());
	}
}