Prolog is a very versatile language, and despite many attempts to build a logic programming language that is equally powerful and convenient to use as Prolog, s

Prolog is a very versatile language, and despite many attempts to build a logic programming language that is equally powerful and convenient to use as Prolog, so far Prolog remains the most popular logic programming language by a huge margin. People who need some variation of Prolog usually add the desired extension on top of Prolog instead of using a different language altogether. This is easy to do in Prolog because its abstract syntax is completely uniform.