The insight (made here by jwr) that TeX and Emacs and Vim are local maximums is a great observation that explains why we are stuck with these three programs. I've used these programs for over a quarter of a century and often wished for shiny, new replacements. Younger HN readers may not realize just how old these programs are.

How in the world did Bill Joy come up with Vi in 1976? It lives on today as the velociraptor of editors, Bram Moolenaar's Vim. I use the T. Rex of editors, Stallman's Gnu Emacs, another dinosaur of software, yet unsurpassed in scope and capability. These are great at what they do and so flexible and extensible that it's difficult for any new project to catch up.

TeX is different. Knuth, one of the greatest computer scientists of all time, created TeX. His choices for development tools were meager, but with the help of /literate programming/, essentially invented by Knuth to write TeX, he wrote TeX using the Pascal programming language in the late 1970s.

TeX, like Emacs and Vi/Vim, has an extension language. TeX has a powerful macro system that allows it to be extended. LaTeX is a set of TeX macros that most users use to create documents. The number of macro packages written for TeX to support every imaginable kind of typesetting (chess notation and boards, music, etc.) is staggering. This accounts for the large size of TeX installations. One can easily download and install every package ever available and be ready to typeset anything. The core TeX program, however, is composed of 1376 extremely well documented paragraphs (small code fragments). It is a pleasure to read through Knuth's literate code, all available as a beautiful book (naturally typeset in TeX).

The features of TeX were effectively frozen in 1985. Knuth kept track of every error in TeX during its development. Since 1985 there have been less than 100 errors found in TeX [1].

The open-source communities around TeX (and Emacs and Vim) make it is difficult for any new project to develop the features that make it worth switching. This is the uphill climb that is facing Patoline. Will it succeed? I'm not sure because many others have tried and failed. Lout was a really good attempt [2], but it seems to have lost steam [3].

[1] http://texdoc.net/texmf-dist/doc/generic/knuth/errata/errorl... [2] http://en.wikipedia.org/wiki/Lout_(software) [3] https://www.ohloh.net/p/lout