Thursday, September 29, 2011

ANTLR Tutorial - Expression Language

ANTLR tool is useful any time you need to create compiler, interpreter or parser of your own language. It takes so called grammar file as an input and generates two classes: lexer and parser.

This post explains what is lexer, what is parser and how to write grammar files to generate them. In the end of the post, you will be able to create a compiler into abstract syntax tree for any simple programming language.

Our example project, a boolean expression language, is written in Java and available on Github. Besides that, everything explained in this post is language independent. Grammar files are the same in all languages.