Many programmers would like to know how to implement an interpreter, so I've written an article ( http://code.google.com/p/cat-language/wiki/HowTheInterpreterWorks ) explaining step-by-step how the Cat interpreter works, using psedo-code and links to the public domain C# source files. The grammar parsing and abstract syntax tree (AST) generation classes were designed to be pluggable into any application, and is also public domain.

Cat is a functional stack-based programming language implemented in C#. While the Cat interpreter itself is released under the MIT license, all of the source code files are public domain. This means you can use them as-is in any project without obligation.