A parser for Mysql -- This excellent example of the power of Antlr 4 is from the Oracle Workbench library at https://github.com/mysql/mysql-workbench/tree/8.0/library/parsers/grammars, and written by Mike Lischke.

Why you should not use a LHS predicate in Antlr Lexers.

Parsing Bison grammars with Antlr. This program parses Bison grammar files using Antlr!

Parsing Antlr grammars with Antlr. This program parses Antlr4 grammar files using Antlr.

Parsing context-free languages in the Antlr lexer. This program demos the use of the well-known expression grammar in the lexer. The rules can't have left recursion, and they all need to be marked with the fragment keyword, but it works.

XPath version 3.1. This C# program contains the latest grammar for XPath, along with 1000+ test cases.

Simple arithmetic example targeting C++ using CMake. This program is unique for a CMake configured Antlr C++ program. This is a concrete example of the somewhat incomplete instructions given in the Antlr website.

Tomaszewski's example. I was combing the web and came across an interesting article by Tomaszewki, of a CFG grammar that doesn't recognize strings like "ww", but a CFG that recognizes string not in the language--an interesting play on what a recognizer could do.

Matlab. This is an example of the Matlab grammar with semantic predicates to correct a tokenization problem with the transpose operator. I've also included the grammar for Octave which I derived by importing the Bison grammar in from the source for Octave.

Antlr grammars with C# action blocks. This is an example of parsing an Antlr targeting C# in action blocks.

PL1. This is grammar for PL/I that I generated from an import of a Bison grammar for the GNU PL/I front end.