Forth is a programming language invented by Charles Moore.
"Forth is an integrated software development environment, an operating system, a programming language but most of all an approach to problem solving. This article is an introduction to Forth. It is not intended to be a tutorial, but an detailed overview of the language and its approach to programming." http://dec.bournemouth.ac.uk/forth/forth.html
The Starting forth tutorial and the gforth implementation are available on Arch Linux.
pacman -S gforth