Using ANTLR with python

Viresh Gupta (~virresh)




This talk aims at introducing ANTLR for python 3, and talk about Abstract Syntax Trees. It will present an overview of the process, the intricacies and will end with a concrete example to show the utility.

ANTLRv4 is a tool that can generate parse trees for any compatible grammar, and provide tools to walk through that tree, so I will illustrate how to use that rather than dwelling more on the theory aspect of the parse trees and boost up the development of language tools.
There is a speciality with ANTLRv4, we can separate context from the grammar (so we can get very close to the expectation that grammars are context free).

I expect the session to be beginner friendly so no pre-requisites save some basic python expected. Also I will cover some basic examples, and also a demo of an actual language grammar to create a meta-program if time permits.
The session is expected to have the following things:

  • What is a grammar ?
  • What are Parse trees and how do they compare to ASTs ?
  • What is ANTLR ? (The parser generator and the runtime provided)
  • How do we use a parse tree ? (dwelling on setting up the environment for ANTLR based development and a short, basic calculator building example)
  • Visitors and Listeners
  • A short real world example on detecting technical constricts in actual programming languages (probably Python itself)


A working knowledge of python basics and some familiarity with some sort of command line interface is ideal
(best suited if you are familiar with any unix/linux based systems, simple script invocation etc)

Content URLs:

A library for ANTLR that is being built by me is available here:
ANTLR's official page:
My blogs related to ANTLR in Python:
An example calculator:

Speaker Info:

I'm a student presently pursuing BTech in CSE at IIIT-Delhi, and am a GSoC student this year at and have been programming various stuff using python for around two years.
I am developing a library to facilitate easy usage of ANTLR for building linting tools.
I've worked on a large array of technologies in any area that I get to know about, ranging from Full stack development, to Systems programming to Language tools. I do my best to pick up and experiment with whatever technologies I can, and I love to learn !

Id: 814
Section: Developer tools and Automation
Type: Talks
Target Audience: Beginner
Last Updated: