On 2017-04-15 10:23 AM, Michael Kerpan wrote: I'm not only talking about the _output_. But my intention isn't to denigrate troff but to show that they are completely different animals. A glance through the TeXbook would confirm. TeX is a complete domain-specific language, page model, and runtime environment (without even discussing its layered frameworks like LaTeX). I admit it took me a few weeks or months of study back in the late 1980s to understand this distinction; previously I had been using a troff-level markup (perhaps even troff-inspired) on Mac called "JustText", which generated PostScript of course. One _can_ typeset books in both troff and TeX, but that doesn't make them at all equivalent. The process and possibilities are different. For example, that simple task of producing two different output formats from the same manuscript, that I mentioned upthread, is made possible by TeX macros. But the sophistication of its page model is also required for any nontrivial layout, table, diagram, math, or just typographic refinement. Some projects _have_ tried to replace TeX. https://tex.stackexchange.com/questions/120271/alternatives-to-latex --T