[pdftex] [Dev-luatex] features request 1

[Hans Hagen]

On 9/2/2021 2:48 PM, Linas Stonys wrote:
> Hi,
> 1) sometimes styles requires to use small vertical indentation between 
> paragraphs
> and naturally  we choose to  use \parskip and it leads to some painful 
> programming dealing with spaces
> For example after float if there will be paragraph  the space will be 
> \|textfloatsep + \parskip.
> |The problem is that there is no control on this and I want to ask 
> consider the possibility to add
> some  tokens list like \everyparskip{} which  would be inserted before 
> \parskip where could be possible
> to check \lastskip:
> 
> FOR EXAMPLE:
> \parskip=5pt
> \everypar{\showthe\lastskip}
> a
> \vskip20pt
> 
> \showthe\lastskip
> b
> \showlists
> \bye
> 
> STDOUT:
>  > 0.0pt.
> <everypar> \showthe \lastskip
> 
> <to be read again>
> a
> l.3 a
> 
> ?
>  > 20.0pt.
> l.6 \showthe\lastskip
> 
> ?
>  > 0.0pt.
> <everypar> \showthe \lastskip
> 
> <to be read again>
> b
> l.7 b
> 
> POSSIBLE PLACE OF \everyparskip:
> .\tenrm a
> .\penalty 10000
> .\glue(\parfillskip) 0.0 plus 1.0fil
> .\glue(\rightskip) 0.0
> \glue 20.0
> ----------- HERE
> \glue(\parskip) 5.0
> \glue(\baselineskip) 5.05556
> \hbox(6.94444+0.0)x469.75499, glue set 444.1994fil, direction TLT
> .\localpar
> ..\localinterlinepenalty=0
> ..\localbrokenpenalty=0
> ..\localleftbox=null
> ..\localrightbox=null
> .\hbox(0.0+0.0)x20.0, direction TLT
> .\tenrm b
> 
> 
> Or \everyparskip{} could be always in the format like 
> \everyparskip{\vskip\parskip} and one could deal with it.
in luametatex we have

\starttext
     test
     \vskip10pt
     \everybeforepar{\writestatus{!}{\the\lastskip}}

     test
\stoptext

(plus more to experiment with)

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