This is a sort of follow-up post to the LaTeX and Metafont post, because it features (among others) the text editor “emacs” which is THE editor for LaTeX.
Emacs is a text editor, whose origins go back to 1975. Emacs is actually mostly either GNU Emacs or XEmacs, but lets forget about these subtleties. The power of Emacs lies in the fact that it can be programmed in (Emacs-) LISP. (LISP is a very old programming language, which was longtime favoured in AI). In this LISP environment, variables and even entire functions can be modified on the fly, without having to recompile or even restart the editor. In particular Emacs can be used as an IDE for developping programms and in particular LaTex programms. For LaTex emacs e.g. highlights commands, paragraphs, it manages errors and it handles the LaTeX compilation etc.
I wouldn’t recommend it for Java programming (Eclipse is better for this job), but for LaTeX it is clearly a must-have.
An last not least there exists incredibly many Emacs Lisp libraries with additional features for the bored programmer, like games such as Tetris and Pong and the above game called Black Box, which exists also with a real solid game board (see image below). Black Box is a nice game which reminds a bit of our game radonge, also if the underlying principles are quite different.
Image from Wikipedia