[pdftex] [Dev-luatex] features request 2

[Hans Hagen]

On 9/2/2021 3:15 PM, Linas Stonys wrote:
> Hi,
> from time to time I face the problem where I need to do something inside 
> tex group (simple group or box or table cell)
> or to mark up some content with tex4ht tags ( or tagging pdf )
> and sometimes \aftergroup is not enough.   So I would like to ask about 
> new token or token list which would
> be inserted before current group end (\beforeendgroup).
> 
> 
> EXAMPLE:
> \showboxdepth=\maxdimen
> \showboxbreadth=\maxdimen
> b
> \hbox{x\aftergroup d  x}
> c
> \showlists
> 
> LOG OUTPUT:
> \tenrm b
> \glue(\spaceskip) 3.33333 plus 1.66666 minus 1.11111
> \hbox(4.30554+0.0)x13.88893, direction TLT
> .\tenrm x
> .\glue(\spaceskip) 3.33333 plus 1.66666 minus 1.11111
> .\tenrm x
> \tenrm d
> \glue(\spaceskip) 3.33333 plus 1.66666 minus 1.11111
> \tenrm c
> 
> 
> COULD BE:
> b
> \hbox{x\beforeendgroup d  x}
> c
> \showlists
> 
> LOG OUTPUT:
> \tenrm b
> \glue(\spaceskip) 3.33333 plus 1.66666 minus 1.11111
> \hbox(4.30554+0.0)x13.88893, direction TLT
> .\tenrm x
> .\glue(\spaceskip) 3.33333 plus 1.66666 minus 1.11111
> .\tenrm x
> .\tenrm d
> \tenrm c
> 
> Of course here needs to think about several same macros how they should 
> queue the content.
In luametatex we have

\starttext

     {[test\atendofgroup{]}

\stoptext

(plus more)

Hans

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