Some sorely needed context:

> [Gforth is] a free, fast, featureful and portable implementation of the Forth 2012 language.

> Gforth runs under GNU, BSD, and similar systems, MS Windows and MacOS X and should not be hard to port to other systems supported by GCC.

If you love HP-RPN calculators, you may love Forth as well. Forth is a very interesting language, I find it a bit too complex for my little brain but give it a spin if, you have 2 free hours