Re: Recent releases of ConTeXt LMTX crash at \starttext when expl3 is loaded

On 8/5/2026 10:13 AM, Max Chernoff via ntg-context wrote:

> I don't think that there's anything that can be done about (1), since
> expl3 isn't slow because it's bloated or poorly-written, but because it
> offers so much functionality. So unless expl3 loses functionality
> somehow, there's probably no way to fix this. But the expl3 load times
> in ConTeXt are _so_ much better since Joseph reimplemented the Unicode
> table stuff in Lua, so maybe there are some other similar places that
> can be sped up.

if people use something that needs expl than i suppose that the loading 
overhead can be neglected .. similar to using tikz

and bloat ...all depends on ones interpretation of bloat but i don't see 
it as my job to check that (last time i peeked at it was when we had to 
look into some latex math/noffonts issue which then also loaded expl and 
i had to get around some stuff in order to figure out the why of that 
issue but i don't want to feedback on somthing that i haven't written 
myself of doesn't relate to context)

> If you can't implement something in Lua, then you're not trying hard
> enough ;).

indeed

> but even I have never used it in ConTeXt before. expl3 is unbeatable for
> when you need to program things using only TeX macros, but expl3 is

even then one should wonder: why program that in tex at all

> It depends. Lua is generally faster than expl3, but not usually by that
> much:
> 
>      https://github.com/latex3/latex3/pull/1557#issuecomment-2226765469
> 
> and expl3 is nearly always faster than if you were to implement
> something using "classic" TeX macros.

oh, benchmarks ... i don't know the code but my personal take on 
benchmarking tex is:

- timing specific macros is a local thing, and as tex is very memory 
intense the cpu cache keep nicely populated; timing lua is very much 
influenced by the GC (and a few other things);

- suboptimal tex or lua code can have quite some impact as can have 
timing itself; i would have to see the specific (small) tex vs lua 
varant to see if it matters and/or scales up (not that i see it as my 
task to optimize latex)

- in practice the time is often spent in different locations, i have 
plenty of cases where i can/could squeeze out performance but it can 
also drown in the rest of the run (it is a bit of pet project to get 
Mikaels math book run under 6 seconds so we're talking accumulated .002 
kind of improvements there)

- that's why whenever i read about timing and performance (also compared 
to tex competitors) i can often see where that smells wrong (also 
related to the task); i know quite well when we've reached the limits 
and/or where there is room for some gain

- run some music in the background, keep the broweer open, and runtime 
get more affected than by small improvements

- of course it can boost one ego a bit when things look faster (even in 
ones perception)

> It definitely takes a bit of practice to get used to it, but I find it
> _much_ easier to read than the \cl@ss@c\@@style of writing macros that
> "plain.tex" and the 2e kernel use.

ok, so relative to @ @ @ @ stuff .. equally bad indeed

>> context and latex are just different things, the fact that there are
>> some cross-package modules is nice but not a target (as people can just
>> use the macro package that provides them what they need)

> This isn't really useful for a markdown package, but it's great for
> drawing packages since it means that you never need to recompile
> unchanged drawings.

could be, but it assumes latex is installed I guess; that said: in these 
times i have to keep in mind (1) not enough memory on the market to 
satisfy endless growth, (2) using older hardware as i can't afford 
upgrading, (3) using less energy to process - occasional fast runs in an 
editing workflow, (4) staying away from dependencies, etc., (5) being 
prepared for the worst

Hans

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