Ubuntu Unleashed 2013 Edition: Covering 12.10 and 13.04, Eighth Edition

Forth

Forth first appeared in the 1970s. It is an interactive, procedural, imperative language with typeless data that runs as a shell. Sets of instructions can be saved and compiled as bytecode programs. It is a very small language by itself and is therefore very useful in boot loaders and embedded systems, and has even been used by NASA in space applications.

On the surface, Forth is a simple language, but it is highly extensible. In essence, a programmer creates a dictionary, beginning with the small set of predefined words. These are combined in new ways to extend the lexicon and create new things that may be done. This is powerful, but it is also dangerous. The lack of standards can lead to less-than-stellar programmers creating unclear ...