What is Factor

Factor is a concatenative, stack-based programming language with high-level features including dynamic types, extensible syntax, macros, and garbage collection. On a practical side, Factor has a full-featured library, supports many different platforms, and has been extensively documented.

The implementation is fully compiled for performance, while still supporting interactive development. Factor applications are portable between all common platforms. Factor can deploy stand-alone applications on all platforms. Full source code for the Factor project is available under a BSD license.

It's been five years since the last release, but Factor 0.99 finally came out. I even contributed a small bit of code and documentation fixes. If you are interested in a modern stack-based programming language or curious about concatenative programming, give Factor a look.