White Lightning was a FIG-Forth implementation produced by Oasis Software in the early to mid 1980s.
Oasis produced versions for the Spectrum ZX (Z80) and Commodore 64 (6502) which sold many thousands of copies in the UK, as well as some in Europe and US. This Forth could multi-task on a Commodore 64 by specifying a Forth word to be executed when an interrupt occurred. It even had up to 255 variable-size software sprites (blit objects).
White Lightning was a complete games writing system for the Sinclair Spectrum ZX comprising a high level, Forth-based, multi-tasking games writing language, and a powerful Sprite Generator Program. Without doubt, it's most innovative feature is its use of interrupts to effectively run two program at once.
Ideal was a subset of FIG-Forth that allowed intermixing of BASIC Lightning and Forth commands to produce fast hybrid code. It had support for scrolling, raster effects (256 sprites), etc. Included was a sprite designer, sprite library, BASIC Lightning, and a compiler that could produce standalone executables. It added over 250 commands to BASIC and was popular in the UK and spawned several user groups.
There was also a product called Dragon-Forth for the Dragon 32/64 (a 6809-based Tandy Color Computer clone).
Additional information can be found at: