Didn't know about this formalism! Are there any Python libraries that support GDL?

It is research code (read very unpolished) but you can get inspiration from pyggp [1]. More specifically, the game_description_language module. I implemented pyggp for my masters thesis. It's a proof of concept and will be iterated upon.

[1] github.com/Entze/pyggp

I learned about GDL several years ago from folk working on General Game Player AIs, that is AI that could play any well described game. They were working primarily in Java at the time. A casual search show that, shockingly, there is no python library available for GDL (yet), they are still using Java.

http://www.ggp.org/

https://github.com/ggp-org/

Interesting, I didn't know about it... Modifying the existing environments' interfaces shouldn't be too difficult. Feel free to submit a PR!

Are there any sample game descriptions for some games ? I have checked all the links but couldn’t find a single example.

At one time there was a Stanford course on the subject of General Game Players. The final project was to submit a player and see how it performed on a small set of games described by GDL. These were variations on Backgammon, Othello, and similar, with some rule changes.

While much of the course material survives [1], those rulesets do not. The only GDL example I could find was the somewhat trivial example of Tic Tac Toe, see section 2.6 Tic Tac Toe Game Rules here [2].

[1]. http://ggp.stanford.edu/public/lessons.php

[2]. http://ggp.stanford.edu/chapters/chapter_02.html

An email for Michael Genesereth, teacher of the course, is on the course website. I might shoot an e-mail and see if he has GDL files to share.