I'm working on modernizing Rosetta Code's infrastructure. Starting with communications. Please accept this time-limited open invite to RC's Slack.. --Michael Mol (talk) 20:59, 30 May 2020 (UTC)

TeX

From Rosetta Code

TeX (the X stands for the greek Χ letter and so pronounced as ch in technics, and written with a lowercase 'e' in imitation of the logo) is a typesetting language and system designed and mostly written by Donald E. Knuth.

See wikipedia TeX for more.

Normally a bare TeX is hardly usable to typeset, so macro packages are often used. The basic macro package given as default is Plain TeX; a very common and widely used macro package is LaTeX, but there are many.