Cat is implemented in C# and the source code is public domain, which means it easily used in commercial or open-source projects, and is compatible with any kind of license you desire. To download the source code through CodeProject.com you have to register, but you can also download the source code from my site at http://www.cat-language.com/download.html.

The article should prove to be interesting for those of you interested in the implementation of interpreters and compilers. Also for those of you interested in using the Cat interpreter (or some variant of Cat) as a scripting add-on to an existing application. Cat of course is also interesting as a stand alone package, and could be used with wrapper applications. Some of the ideas I for projects I'd like to develop are:

• A Cat with macros extension language
• An EcmaScript style syntax wrapper around Cat
• A Scheme to Cat translator
• An implementation of Cat without types in C++, Scheme and F#/OCaml
• A Cat to C translator

Cat is an extremely easy to implement language, if you disregard type inference. I would estimate that it shouldn't take more than one or two person weeks to implement in a modern language, assuming you leave out all type checking and type inference code and you use the pre-existing code as a model.

This means that Cat is also easy to port, translate to, and translate from. I expect over the next year to see various implementation of Cat pop up all over the place This is based on the interest expressed by various people over the internet.

Cat can also be easily used as a scripting language to extend applications. If you don't like the Cat postfix notation, it is a relatively easy task to implement a prefix notation front-end. In fact this one of the projects on my to-do list.