Am Freitag, 21. Juni 2024, 19:00:03 MESZ schrieb Hans Hagen via ntg-context:
> -- support for stacking at the tex end (maybe for presentations)
> 
> \starttext
> 
> \definestacking[one]
> \definestacking[two]
> 
> \startbuffer
> This is a test \stacking [one] {and a proof} of \stacking [two] 
> {concept} indeed
> \stacking [one] {\blackrule [width=4cm]} is it and the question is how 
> \stacking
> [two] {\scale [s=2] {fancy}} we can go
> 
> \startstacking[one]
> \startformula
>      \sqrt{1+x}
> \stopformula
> \stopstacking
> 
> and how useful \stacking[two]{\inframed{it}} is.
> \stopbuffer
> 
> \startstackingsteps[one,two,{one,two}]
>      \startTEXpage[offset=1ts]
>          \getbuffer
>      \stopTEXpage
> \stopstackingsteps
> 
> \startTEXpage[offset=1ts] \setupstacking[criterium={one}]     \getbuffer 
> \stopTEXpage
> \startTEXpage[offset=1ts] \setupstacking[criterium={two}]     \getbuffer 
> \stopTEXpage
> \startTEXpage[offset=1ts] \setupstacking[criterium={one,two}] \getbuffer 
> \stopTEXpage
> 
> \stoptext

Very nice, thank you!

I see some similarities to the "visible on" technique [1], I posted in a previous thread.
What comes there really handy are range specifiers, what seems not possible with this interface.
For example: "visible on=<2->" renders the content on every page except the first one
or "visible on=<1-5,13-15>" on the first page up to the fifth page and from page 13 to 15.

The mechanism stems from the Beamer overlay specifications, see section 9.3 of the manual [2]
and can be much more complicated with modes (section 9.6.2).

To add this to the new interface, if you want that, the stack layers above need some kind of order,
which is implicit for numbers:
```
\definestacking{one}
\definestacking{two}
\definestacking{three}
\definestackingorder{one,two, three}
...
\setupstacking[criterium={one-three}]
```
The order could also be implicitly defined after the order of the \definestacking calls.

Or would it be possible to have numbers always automatically (additionally) available as stacking layer?
So that this "just" works:
```
\startbuffer
This is a test \stacking [1] {and a proof} of \stacking [2] {concept} indeed.
\stopbuffer
...
\setupstacking[criterium={1-}]
```

I also wondered, if it is possible to define a lot of layers semiautomatically in Lua
(in some graphics I needed around 20 layers). It seems that numbers in layer names currently are not allowed.
Is code like this possible somehow?

```
\startluacode
for i = 1, 20 do
    context.definestacking(string.format("l\letterpercent.d", i))
end
\stopluacode
```

Gerion


[1] https://github.com/luhsra/texmf/blob/main/tex/latex/beamertools/beamertools.sty
[2] https://ctan.org/pkg/beamer