[NTG-context] protected macro vs protected luacall

[Hans Hagen]

On 1/27/2023 12:03 PM, Henri Menke via ntg-context wrote:

> How much do you think would break if protected luacall were treated
> like protected macros after \the in the engine?

That kind of incompatibility is no option (I'm not going to analyze it 
for mkiv let along other macro package usage which is out of my scope).

> That would probably need an extra branch in the switch(cur_cmd) in
> scan_something_internal. Currently protected luacall just goes to the
> default branch (You can't use ...).
For various reasons luatex got frozen around version 1 and demand for 
stability (which also excluded experiments) is one of them. So, one has 
to work with what one gets (not much different from the rest of tex 
functionality). With careful coding the performance hit is not that 
large and machines still get a bit get faster so that compensates it 
anyway. Although some low level approaches can bring benefits it's never 
homogenious and largely depends on use cases.

Hans

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