Gosling Emacs

Gosling Emacs (often shortened to "Gosmacs" or "gmacs") is a discontinued Emacs implementation written in 1981 by James Gosling in C. Its extension language, Mocklisp, has a syntax that appears similar to Lisp, but Mocklisp does not have lists or any other structured datatypes. Gosling initially allowed Gosling Emacs to be redistributed with no formal restrictions, but later sold it to UniPress.

Gosling Emacs was especially noteworthy because of the effective redisplay code, which used a dynamic programming technique to solve the classical string-to-string correction problem. The algorithm was quite sophisticated; that section of the source was headed by a skull-and-crossbones in ASCII art, warning would-be improver that even if they thought they understood how the display code worked, they probably did not.

Since Gosling had permitted its unrestricted redistribution, Richard Stallman used some Gosling Emacs code in the initial version of GNU Emacs. Among other things, he rewrote part of the Gosling code headed by the skull-and-crossbones comment and made it "...shorter, faster, clearer and more flexible."