The ANTLR Parser Generator

These web page discuss my experience with a parser generator called ANTLR. ANTLR is a second generation parser generator. The first generation was PCCTS. ANTLR is implemented in Java, but will generate parsers in both Java and C++.

I have found that the learning curve for ANTLR is very steep. However, this is not unique to ANTLR. YACC/Bison also takes some effort to learn. The one advantage of YACC/Bison is that there are a number of good books on their use. ANTLR does not have as wide a user base yet. The Web site includes HTML documentation for ANTLR. However, ANTLR is complicated and I have found that this documentation provides only a starting point. I have spent many hours working with ANTLR and working on small examples to learn the tool. In the spirit of free software I am publishing these Web pages in the hope that they will help other ANTLR users. As my use of ANTLR progresses I will update these Web pages, so this is definitely a work in progress.

Since ANTLR is an open source project (under the gentle guidance of Terence Parr), there are a number of active contributors. One of these is Ric Klaren. Ric publishes an ANTLR development snapshot. (

The main discussion group for ANTLR is hosted by Yahoo Groups and can be found at The archives and current messages can be viewed, since this is a public forum. To post you need to join the group. The Yahoo user interface leaves a bit to be desired. The number of messages posted per month is shown at the bottom of the page. Click on the current month and you will see the latest discussion.

A great deal of credit should be given to anyone who puts the effort, time and creativity into building something. Many people will come along and criticize the works of others, but most of these critics have never created anything significant themselves. The critics have never struggled with the issues that the creator of the work did and in most cases could not create a similar work themselves.

ANTLR is a significant piece of software and a great deal of credit is due to Terence Parr, Peter Wells and the other developers and maintainers of ANTLR. In these Web pages I discuss some of the pros and cons of ANTLR, as I see them. But I recognize the efforts of the authors and maintainers of ANTLR. They stepped up and created the software.

Ian Kaplan, July 11, 1999
Revised April 13, 2000

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