Re: [NTG-context] Setting and measuring boxes TeX/Lua

[Hans Hagen]

Hi Jano,

It's not clear to me what you want to measure when but here is a weekend 
playground (you're locked down anyway).


\def\MacroJano#1%
  {\writestatus{JANO}{ONE}
   \setbox0=\hbox\bgroup\xmlflush{#1}\egroup}

\startluacode
function document.FunctionJano(id)
context.writestatus("JANO","ZERO")
token.expand_macro("MacroJano",true,id)
context("%p",tex.box[0].width)
context.writestatus("JANO","TWO")
end
\stopluacode

\startbuffer[doc]


one
one two
one two three

\stopbuffer

\startxmlsetups xml:name
\xmlsetsetup{#1}{*}{xml:*}
\stopxmlsetups

\xmlregistersetup{xml:name}

\startxmlsetups xml:section
width: \ctxlua{document.FunctionJano("#1")}\par
\stopxmlsetups

\startxmlsetups xml:document
\xmlflush{#1}
\stopxmlsetups

\starttext

\xmlprocessbuffer{xml:name}{doc}{}

\stoptext

A clue: token.expand_macro will kind of 'run a local tex job'.

If this works for you. you know the price you have to pay ... wikify

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: [NTG-context] Setting and measuring boxes TeX/Lua

[Jano Kula]

Hello again, Hans!

On Thu, 26 Nov 2020 at 09:18, Hans Hagen  wrote:

> (this mechanism is already kind of old, there are also other cheats
> possible)
>

Diving into functions and using context.stepwise() worked, until I've got
to: /cldf-stp.lua:48: bad argument #1 to 'resume' (thread expected) and
other errors. It was triar/error approach, not exactly knowing how
context.stepwise() works, and I was some more lua functions and iterations
before needing expansion.

Therefore I've changed the strategy (cannot give up):

   - Create named buffers with formatted content (and store measures)
   before they are needed.
   - When needed, use the reference to the buffer.

Tests looked promising. After \starttext buffers and measures are known
(both TeX & Lua). Also tested in functions, etc.
But inside the first \xmlsetup, they are not expanded anymore, they are
typeset (like \typebuffer).

   - How to have them expanded in \xmlsetup?
   - Is other mechanism better suited for storing typeset blocks than
   buffers (and will survive \xmlsetup)?
   - If none of them is possible, what are the *other **cheats *then?

Thanks,
Jano

MWE attached

% BUFFERS
\startluacode
-- fill buffers
for i=1,1000 do
local content = "framed-" .. i
context.startbuffer( { i } )
context.StartBox()
context.bold(i)context.par()
context.color( { "red" }, content )
context.StopBox()
context.copy(false,0)
context.stopbuffer()
print(">>", i)
end
\stopluacode

\def\StartBox{\setbox0=\hbox\bgroup\framed[width=50mm,
   background=color,
   backgroundcolor=gray,
   frame=off,align={flushleft}]%
   \bgroup%
\vbox\bgroup}
\def\StopBox{\egroup\egroup\egroup}% close vbox, framed, hbox

\def\MeasureBuffer[#1]{\setbox0\hbox{\getbuffer[#1]}%
   ht: \the\ht0\par}


% XML
\startbuffer[doc]


section
section

\stopbuffer

\startxmlsetups xml:name
\xmlsetsetup{\xmldocument}{*}{-}
\xmlsetsetup{\xmldocument}{document}{xml:name:*}
\stopxmlsetups

\xmlregistersetup{xml:name}

\startxmlsetups xml:name:document
\Title{inside xml:name:document}
\Title{TeX}
\MeasureBuffer[333]
\getbuffer[333]
\Title{Lua}
\startluacode
context.MeasureBuffer({"444"})
context.getbuffer({"444"})
\stopluacode
\stopxmlsetups

\def\Title#1{\blank{\bf #1}\par}


\starttext

\Title{TeX}
\MeasureBuffer[111]
\getbuffer[111]

\Title{Lua}
\startluacode
context.MeasureBuffer({"222"})
context.getbuffer({"222"})
\stopluacode

\xmlprocessbuffer{xml:name}{doc}{}

\stoptext


xml-buffers.tex
Description: TeX document
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Re: [NTG-context] Setting and measuring boxes TeX/Lua

[Hans Hagen]

On 11/25/2020 10:28 PM, Jano Kula wrote:

Hello Hans!

On Wed, 25 Nov 2020 at 21:25, Hans Hagen > wrote:


\startluacode
context.stepwise (function()
      context.step()
end)
\stopluacode


Thank you very much!

I was trying context.stepwise several times (and \dowithnextbox, 
\nextboxht and other things). I bet there was no example of empty 
context.step().


The usage was: stepping in TeX end with 
context.step("\\texcommands\\with\\doubleslashes") without leaving Lua.

What is the purpose of empty context.step()? Knocking on TeX's door?

no, kind of quit, goto tex and then pickup again (coroutine magic)

(this mechanism is already kind of old, there are also other cheats 
possible)


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: [NTG-context] Setting and measuring boxes TeX/Lua

[Jano Kula]

Hello Hans!

On Wed, 25 Nov 2020 at 21:25, Hans Hagen  wrote:

> \startluacode
> context.stepwise (function()
>  context.step()
> end)
> \stopluacode
>

Thank you very much!

I was trying context.stepwise several times (and \dowithnextbox,
\nextboxht and
other things). I bet there was no example of empty context.step().

The usage was: stepping in TeX end with
context.step("\\texcommands\\with\\doubleslashes") without leaving Lua.
What is the purpose of empty context.step()? Knocking on TeX's door?

Jano
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Re: [NTG-context] Setting and measuring boxes TeX/Lua

[Hans Hagen]

On 11/25/2020 7:31 PM, Jano Kula wrote:

Hello!

I would like to set framed boxes, measure their dimensions and proceed 
based on the measurement. It is a combination of TeX and Lua ends.


  * Boxes are set on the TeX side. Stacking boxes (hbox, framed, vbox)
in Lua looked too complex.
  * The content of the inner box is set on the Lua side (some computations).

On TeX side boxes and their dimensions are accessible, but not at Lua 
side, until luacode is finished (iterations over boxes happen here). I 
would say Hans already named the problem in the list: /that is always 
tricky as what happens is postponing till the group ends/.


Do you have an idea how to expand the box sooner or would you use a 
different approach?


Sorry for longer MWE (attached also).

Thank you,
Jano

\def\StartBox{\setbox0=\hbox\bgroup% open hbox
                 \framed[frame=on]\bgroup% open framed
                     \vbox\bgroup% open vbox (\par needed)
              }
\def\StopBox{\egroup\egroup\egroup% close vbox, framed, hbox
              \setvariable{Test}{Height}{\the\ht0}%
             }%

\startluacode
ctx = context

function TestBox()
     ctx("TeX Box: ")    ctx.copy(false,0)ctx.par()
     ctx("TeX Getvar: ") ctx.getvariable("Test", "Height")ctx.par()
     var = tokens.getters.macro(tokens.getters.macro("??variables") .. 
"Test:Height")

     ctx("Lua Type: ")   ctx(type(var))ctx.par()
     ctx("Lua Value: ")  ctx(var)ctx.par()
end
\stopluacode

\starttext

\startluacode
     ctx.bold("First luacode (more boxes)")ctx.par()
     ctx.StartBox()
     ctx("AAA")ctx.par()
     ctx("BBB")ctx.par()
     ctx.StopBox()
     TestBox()
     ctx.StartBox()
     ctx("CCC")ctx.par()
     ctx.StopBox()
     TestBox()
\stopluacode

\blank[4*big]

\startluacode
     ctx.bold("Second luacode (last content of box0)")ctx.par()
     TestBox()
\stopluacode

\stoptext

\startluacode
 context.stepwise (function()
ctx.bold("First luacode (more boxes)")ctx.par()
ctx.StartBox()
ctx("AAA")ctx.par()
ctx("BBB")ctx.par()
ctx.StopBox()
context.step()
TestBox()
context.step()
ctx.StartBox()
ctx("CCC")ctx.par()
ctx.StopBox()
context.step()
TestBox()
context.step()
end)
\stopluacode

-
  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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