Getting dimensions in Lua

Getting dimensions in Lua

[Jairo A. del Rio]

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Hi, list.

I want to get some dimensions in Lua. See, for instance

\starttext

\the\dimexpr\availablehsize\relax %say, 426pt

\stoptext

Is there an equivalent in ConTeXt for Lua, i.e. without passing values from
TeX or, at least, using only Lua commands? Thank you in advance.

Best wishes,

Jairo

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Re: Getting dimensions in Lua

[Hans Hagen]

On 1/18/2021 1:58 AM, Jairo A. del Rio wrote:
> Hi, list.
> 
> I want to get some dimensions in Lua. See, for instance
> 
> \starttext
> 
> \the\dimexpr\availablehsize\relax %say, 426pt
> 
> \stoptext
> 
> Is there an equivalent in ConTeXt for Lua, i.e. without passing values 
> from TeX or, at least, using only Lua commands? Thank you in advance.
tex being tex, there is always a way ...

1: \number\dimexpr\availablehsize\relax

2: \startluacode
 
token.set_macro(tex.ctxcatcodes,"temp","\\scratchdimen\\availablehsize")
     token.expand_macro("temp")
     context(tex.getdimen("scratchdimen"))
\stopluacode

3: \startluacode
 
token.set_macro(tex.ctxcatcodes,"temp","\\scratchdimen\\availablehsize")
     tex.runlocal("temp")
     context(tex.getdimen("scratchdimen"))
\stopluacode

4: \startluacode
     tex.print("\\scratchdimen\\availablehsize")
     tex.pushlocal()
     tex.poplocal()
     context(tex.getdimen("scratchdimen"))
\stopluacode

5: \startluacode
     tex.print("\\dimensiondef\\temp\\availablehsize")
     tex.pushlocal()
     tex.poplocal()
     context(tex.getdimensionvalue("temp"))
\stopluacode

\def\calculateavailablehsize{\dimensiondef\temp\availablehsize}

6: \startluacode
     token.expand_macro("calculateavailablehsize")
     context(tex.getdimensionvalue("temp"))
\stopluacode

\newtoks\tcalculateavailablehsize 
\tcalculateavailablehsize{\dimensiondef\temp\availablehsize}

7: \startluacode -- mkiv
     tex.runtoks("tcalculateavailablehsize")
     context(tex.getdimensionvalue("temp"))
\stopluacode

i'm (still) considering a way to flag a macro to be an expression (or 
value) but there are several variants possible but normally it takes a 
while before i decide what makes most sense (as i need to apply it in 
real code to see if it looks nice)

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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Re: Getting dimensions in Lua

[Taco Hoekwater]

> On 18 Jan 2021, at 10:45, Hans Hagen <j.hagen@xs4all.nl> wrote:
> 
> On 1/18/2021 1:58 AM, Jairo A. del Rio wrote:
>> Hi, list.
>> I want to get some dimensions in Lua. See, for instance
>> \starttext
>> \the\dimexpr\availablehsize\relax %say, 426pt
>> \stoptext
>> Is there an equivalent in ConTeXt for Lua, i.e. without passing values from TeX or, at least, using only Lua commands? Thank you in advance.
> tex being tex, there is always a way ...

There is also this option:

   % function returns scaled points
   \startluacode
   function availablehsize() 
      local l = tex.dimen.hsize - tex.skip.leftskip.width - tex.skip.rightskip.width
      if tex.count.hangafter<0 then
         local h = tex.dimen.hangindent
         if h>0 then  l = l - h else l = l + h end
      end
      return l 
   end
   \stopluacode

But I suspect that there are multiple cases where this does not work
(like when used in horizontal mode, for example if the par setting changes 
before the \par is seen, or when there is data in the local par node)

Best wishes,
Taco

— 
Taco Hoekwater              E: taco@bittext.nl
genderfluid (all pronouns)







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___________________________________________________________________________________

Re: Getting dimensions in Lua

[Jairo A. del Rio]

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Woah, nice! I was trying to pass some values to MetaPost via Lua (usual
laziness to learn macro languages). Thank you a lot, especially because I
was looking at the wrong functions in the token namespace. I'll upload a
more specific example soon while I polish some code. Very thankful.

Jairo :)

El lun, 18 de ene. de 2021 a la(s) 05:02, Taco Hoekwater (taco@bittext.nl)
escribió:

>
>
> > On 18 Jan 2021, at 10:45, Hans Hagen <j.hagen@xs4all.nl> wrote:
> >
> > On 1/18/2021 1:58 AM, Jairo A. del Rio wrote:
> >> Hi, list.
> >> I want to get some dimensions in Lua. See, for instance
> >> \starttext
> >> \the\dimexpr\availablehsize\relax %say, 426pt
> >> \stoptext
> >> Is there an equivalent in ConTeXt for Lua, i.e. without passing values
> from TeX or, at least, using only Lua commands? Thank you in advance.
> > tex being tex, there is always a way ...
>
> There is also this option:
>
>    % function returns scaled points
>    \startluacode
>    function availablehsize()
>       local l = tex.dimen.hsize - tex.skip.leftskip.width -
> tex.skip.rightskip.width
>       if tex.count.hangafter<0 then
>          local h = tex.dimen.hangindent
>          if h>0 then  l = l - h else l = l + h end
>       end
>       return l
>    end
>    \stopluacode
>
> But I suspect that there are multiple cases where this does not work
> (like when used in horizontal mode, for example if the par setting changes
> before the \par is seen, or when there is data in the local par node)
>
> Best wishes,
> Taco
>
> —
> Taco Hoekwater              E: taco@bittext.nl
> genderfluid (all pronouns)
>
>
>
>
>
>
>
>

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___________________________________________________________________________________

Re: Getting dimensions in Lua

[Jairo A. del Rio]

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To be wikified (by me, obviously). Thank you for such a great number of
alternatives.

Jairo :)

El lun, 18 de ene. de 2021 a la(s) 04:45, Hans Hagen (j.hagen@xs4all.nl)
escribió:

> On 1/18/2021 1:58 AM, Jairo A. del Rio wrote:
> > Hi, list.
> >
> > I want to get some dimensions in Lua. See, for instance
> >
> > \starttext
> >
> > \the\dimexpr\availablehsize\relax %say, 426pt
> >
> > \stoptext
> >
> > Is there an equivalent in ConTeXt for Lua, i.e. without passing values
> > from TeX or, at least, using only Lua commands? Thank you in advance.
> tex being tex, there is always a way ...
>
> 1: \number\dimexpr\availablehsize\relax
>
> 2: \startluacode
>
> token.set_macro(tex.ctxcatcodes,"temp","\\scratchdimen\\availablehsize")
>      token.expand_macro("temp")
>      context(tex.getdimen("scratchdimen"))
> \stopluacode
>
> 3: \startluacode
>
> token.set_macro(tex.ctxcatcodes,"temp","\\scratchdimen\\availablehsize")
>      tex.runlocal("temp")
>      context(tex.getdimen("scratchdimen"))
> \stopluacode
>
> 4: \startluacode
>      tex.print("\\scratchdimen\\availablehsize")
>      tex.pushlocal()
>      tex.poplocal()
>      context(tex.getdimen("scratchdimen"))
> \stopluacode
>
> 5: \startluacode
>      tex.print("\\dimensiondef\\temp\\availablehsize")
>      tex.pushlocal()
>      tex.poplocal()
>      context(tex.getdimensionvalue("temp"))
> \stopluacode
>
> \def\calculateavailablehsize{\dimensiondef\temp\availablehsize}
>
> 6: \startluacode
>      token.expand_macro("calculateavailablehsize")
>      context(tex.getdimensionvalue("temp"))
> \stopluacode
>
> \newtoks\tcalculateavailablehsize
> \tcalculateavailablehsize{\dimensiondef\temp\availablehsize}
>
> 7: \startluacode -- mkiv
>      tex.runtoks("tcalculateavailablehsize")
>      context(tex.getdimensionvalue("temp"))
> \stopluacode
>
> i'm (still) considering a way to flag a macro to be an expression (or
> value) but there are several variants possible but normally it takes a
> while before i decide what makes most sense (as i need to apply it in
> real code to see if it looks nice)
>
> Hans
>
> -----------------------------------------------------------------
>                                            Hans Hagen | PRAGMA ADE
>                Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>         tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
>

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If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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wiki     : http://contextgarden.net
___________________________________________________________________________________