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/CSharpTarget.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.ErrorType;
import org.stringtemplate.v4.NumberRenderer;
import org.stringtemplate.v4.STErrorListener;
import org.stringtemplate.v4.STGroup;
import org.stringtemplate.v4.STGroupFile;
import org.stringtemplate.v4.StringRenderer;
import org.stringtemplate.v4.misc.STMessage;

import java.util.*;

public class CSharpTarget extends Target {
	protected static final HashSet<String> reservedWords = new HashSet<>(Arrays.asList(
		"abstract",
		"as",
		"base",
		"bool",
		"break",
		"byte",
		"case",
		"catch",
		"char",
		"checked",
		"class",
		"const",
		"continue",
		"decimal",
		"default",
		"delegate",
		"do",
		"double",
		"else",
		"enum",
		"event",
		"explicit",
		"extern",
		"false",
		"finally",
		"fixed",
		"float",
		"for",
		"foreach",
		"goto",
		"if",
		"implicit",
		"in",
		"int",
		"interface",
		"internal",
		"is",
		"lock",
		"long",
		"namespace",
		"new",
		"null",
		"object",
		"operator",
		"out",
		"override",
		"params",
		"private",
		"protected",
		"public",
		"readonly",
		"ref",
		"return",
		"sbyte",
		"sealed",
		"short",
		"sizeof",
		"stackalloc",
		"static",
		"string",
		"struct",
		"switch",
		"this",
		"throw",
		"true",
		"try",
		"typeof",
		"uint",
		"ulong",
		"unchecked",
		"unsafe",
		"ushort",
		"using",
		"virtual",
		"values",
		"void",
		"volatile",
		"while"
	));

	protected static final Map<Character, String> targetCharValueEscape;
	static {
		// https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/strings/#string-escape-sequences
		HashMap<Character, String> map = new HashMap<>();
		addEscapedChar(map, '\'');
		addEscapedChar(map, '\"');
		addEscapedChar(map, '\\');
		addEscapedChar(map, '\0', '0');
		addEscapedChar(map, (char)0x0007, 'a');
		addEscapedChar(map, (char)0x0008, 'b');
		addEscapedChar(map, '\f', 'f');
		addEscapedChar(map, '\n', 'n');
		addEscapedChar(map, '\r', 'r');
		addEscapedChar(map, '\t', 't');
		addEscapedChar(map, (char)0x000B, 'v');
		targetCharValueEscape = map;
	}

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

	@Override
	public Map<Character, String> getTargetCharValueEscape() {
		return targetCharValueEscape;
	}

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

	@Override
	protected String escapeWord(String word) {
		return "@" + word;
	}

	@Override
	protected STGroup loadTemplates() {
		// override the superclass behavior to put all C# templates in the same folder
		STGroup result = new STGroupFile(CodeGenerator.TEMPLATE_ROOT+"/CSharp/"+ getLanguage()+STGroup.GROUP_FILE_EXTENSION);
		result.registerRenderer(Integer.class, new NumberRenderer());
		result.registerRenderer(String.class, new StringRenderer());
		result.setListener(new STErrorListener() {
			@Override
			public void compileTimeError(STMessage msg) {
				reportError(msg);
			}

			@Override
			public void runTimeError(STMessage msg) {
				reportError(msg);
			}

			@Override
			public void IOError(STMessage msg) {
				reportError(msg);
			}

			@Override
			public void internalError(STMessage msg) {
				reportError(msg);
			}

			private void reportError(STMessage msg) {
				getCodeGenerator().tool.errMgr.toolError(ErrorType.STRING_TEMPLATE_WARNING, msg.cause, msg.toString());
			}
		});

		return result;
	}

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

	@Override
	protected String escapeChar(int v) {
		return String.format("\\x%X", v);
	}
}

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