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/codegen/target/JavaScriptTarget.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.codegen.target;

import org.antlr.v4.codegen.CodeGenerator;
import org.antlr.v4.codegen.Target;
import org.antlr.v4.tool.ast.GrammarAST;
import org.stringtemplate.v4.STGroup;
import org.stringtemplate.v4.StringRenderer;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;

public class JavaScriptTarget extends Target {
	/** Source: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar */
	protected static final HashSet<String> reservedWords = new HashSet<>(Arrays.asList(
		"break", "case", "class", "catch", "const", "continue", "debugger",
		"default", "delete", "do", "else", "export", "extends", "finally", "for",
		"function", "if", "import", "in", "instanceof", "let", "new", "return",
		"super", "switch", "this", "throw", "try", "typeof", "var", "void",
		"while", "with", "yield",

		//future reserved
		"enum", "await", "implements", "package", "protected", "static",
		"interface", "private", "public",

		//future reserved in older standards
		"abstract", "boolean", "byte", "char", "double", "final", "float",
		"goto", "int", "long", "native", "short", "synchronized", "transient",
		"volatile",

		//literals
		"null", "true", "false",

		// misc
		"rule", "parserRule"
	));

	public JavaScriptTarget(CodeGenerator gen) {
		super(gen);
	}

	@Override
	protected Set<String> getReservedWords() {
		return reservedWords;
	}

	@Override
	public int getInlineTestSetWordSize() {
		return 32;
	}

	@Override
	protected STGroup loadTemplates() {
		STGroup result = super.loadTemplates();
		result.registerRenderer(String.class, new JavaStringRenderer(), true);
		return result;
	}

	protected static class JavaStringRenderer extends StringRenderer {

		@Override
		public String toString(Object o, String formatString, Locale locale) {
			if ("java-escape".equals(formatString)) {
				// 5C is the hex code for the \ itself
				return ((String)o).replace("\\u", "\\u005Cu");
			}

			return super.toString(o, formatString, locale);
		}

	}

	@Override
	public boolean wantsBaseListener() {
		return false;
	}

	@Override
	public boolean wantsBaseVisitor() {
		return false;
	}

	@Override
	public boolean supportsOverloadedMethods() {
		return false;
	}

	@Override
	public boolean isATNSerializedAsInts() {
		return true;
	}
}

⏎ org/antlr/v4/codegen/target/JavaScriptTarget.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