ANTLR is a powerful parser generator for multiple programming languages including Java.

ANTLR contains 2 major modules:

• Runtime - For building and executing parsers/lexers generated in Java.
• Tool (The Parser Generator) - For generating parsers/lexers Java class.

ANTLR Tool Source Code files are provided in the distribution packge (antlr4-4.10.1.zip). You can download them at ANTLR Website.

You can also browse the source code below:

⏎ org/antlr/v4/parse/ToolANTLRParser.java

/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.parse;

import org.antlr.runtime.NoViableAltException;
import org.antlr.runtime.Parser;
import org.antlr.runtime.RecognitionException;
import org.antlr.runtime.TokenStream;
import org.antlr.v4.Tool;
import org.antlr.v4.tool.ErrorType;

/** Override error handling for use with ANTLR tool itself; leaves
 *  nothing in grammar associated with Tool so others can use in IDEs, ...
 */
public class ToolANTLRParser extends ANTLRParser {
	public Tool tool;

	public ToolANTLRParser(TokenStream input, Tool tool) {
		super(input);
		this.tool = tool;
	}

	@Override
	public void displayRecognitionError(String[] tokenNames,
										RecognitionException e)
	{
		String msg = getParserErrorMessage(this, e);
		if ( !paraphrases.isEmpty() ) {
			String paraphrase = paraphrases.peek();
			msg = msg+" while "+paraphrase;
		}
	//	List stack = getRuleInvocationStack(e, this.getClass().getName());
	//	msg += ", rule stack = "+stack;
		tool.errMgr.syntaxError(ErrorType.SYNTAX_ERROR, getSourceName(), e.token, e, msg);
	}

	public String getParserErrorMessage(Parser parser, RecognitionException e) {
		String msg;
		if ( e instanceof NoViableAltException) {
			String name = parser.getTokenErrorDisplay(e.token);
			msg = name+" came as a complete surprise to me";
		}
		else if ( e instanceof v4ParserException) {
			msg = ((v4ParserException)e).msg;
		}
		else {
			msg = parser.getErrorMessage(e, parser.getTokenNames());
		}
		return msg;
	}

	@Override
	public void grammarError(ErrorType etype, org.antlr.runtime.Token token, Object... args) {
		tool.errMgr.grammarError(etype, getSourceName(), token, args);
	}
}

⏎ org/antlr/v4/parse/ToolANTLRParser.java

Or download all of them as a single archive file:

File name: antlr-tool-4.10.1-sources.jar
File size: 347718 bytes
Release date: 2022-04-15
Download 

⇒ Donwload antlr4-4.10.1.zip

⇐ ANTLR Runtime Source Code

⇑ Download and Review ANTLR Parser Generator

⇑⇑ FAQ for ANTLR Parser Generator