Omikhleia

In action: 

> ... to ease the transition from TeX. I don't think the same way. Most lightweight markup language engines claim support for TeX-like. I'have my Djot and Markdown inputters in...

> SILE is a modern language with an actual syntax and semantics. I'm afraid I don't understand what this sentence means.

But this is totally unrelated with the discussion at stakes in this issue, isn't it? Or am I missing the point?

> The link is that you want to have TeX-compatible syntax, and that it is very difficult to mimic what TeX would do in all cases, without reimplementing TeX’s Turing-complete...

Additional reference for the TeX-math case: https://github.com/jgm/texmath/blob/master/src/Text/TeXMath/Readers/TeX.hs#L687-L691

Besides the above-mentioned old Firefox test, another interesting test to check: http://eyeasme.com/Joe/MathML/MathML_browser_test.html (EDIT: It has both the TeX sources and the MathML code = we could also use it for...

And of course, another great series of examples and checks... is just the MathML [test suite](https://www.w3.org/Math/testsuite/build/main/toc-full.xhtml)... I just started trying some of the "torture" tests, and it's... interesting ;)

N.B. I can consider TeX math-like `\sqrt[n]{base}` separately, after this and #2140 are merged, as it touches the same parts of the code.

> N.B. The proposed extra check is what the fallback shaper does... ... Which might be a harfbuzz-specific approach, however (i.e. I am not sure other shapers are expected to...