Game Description Language
Game Definition Language, or GDL, is a language designed by Michael Genesereth as part of the General Game Playing Project at Stanford University, California. GDL describes the state of a game as a series of facts, and the game mechanics as logical rules.
Purpose of GDL
Quoted in an article in New Scientist [1], Genesereth pointed out that although Deep Blue is able to play chess at a grandmaster level, it is incapable of playing checkers at all. As both games can be described in GDL, an algorithm designed to 'play' GDL would be able to play both chess and checkers.
Specification
GDL is a variant of Datalog, and the syntax is largely the same.