A functional programming language

Qpad
Free
Offline
http://q-lang.sourceforge.net/index.html

Q is an interpreted, dynamically typed functional programming language based on term rewriting which allows you to define functions using symbolic equations. It works on (32 bit) Linux, OS X, Unix and Windows, and comes with a bunch of useful libraries which turn it into a practical programming tool. The Q programming system is free software distributed under the GPL.