Why Factor?

The Factor programming language combines powerful language features with a full-featured library. 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.

• Screenshots: Mac OS X, Windows
• Learn more about Factor
• Get started programming with Factor
• Get answers to frequently-asked questions
• Read Factor reference documentation online
• Learn more about concatenative programming

Most of the above links point to pages on the concatenative.org wiki.

Show me some code!

Factor belongs to the family of concatenative languages: this means that, at the lowest level, a Factor program is a series of words (functions) that manipulate a stack of references to dynamically-typed values. This gives the language a powerful foundation which allows many abstractions and paradigms to be built on top. Reload this page to see a random code example below.

USING: accessors kernel math math.constants
math.functions prettyprint ;
IN: shapes

TUPLE: circle radius ;
TUPLE: rectangle width height ;

GENERIC: area ( shape -- area )
M: circle area radius>> sq pi * ;
M: rectangle area [ width>> ] [ height>> ] bi * ;

rectangle new 10 >>width 20 >>height area .

See the example programs page on the wiki for more.