[NTG-context] Callbacks in LuaMetaTeX
Hi list,
I've been playing around with some of the Lua callbacks in LuaMetaTeX,
and I have a few questions/comments.
Context: I'm writing a Plain/LaTeX/ConTeXt module called
"lua-widow-control" that uses Lua callbacks to automatically remove
widows and orphans from documents. The relevant Lua code is at:
https://github.com/gucci-on-fleek/lua-widow-control/blob/master/source/lua-widow-control.lua
in case you're curious about how I'm using these callbacks, but you
shouldn't need to look there since this email is self-contained.
1. In LMTX, calling "tex.linebreak" produces a
luatex warning > tex: left parfill skip is gone
warning. I don't get this warning in Plain LuaTeX, LuaLaTeX, or MkIV,
so I think that it's specific to LuaMetaTeX. The LuaMetaTeX manual
hardly mentions "left parfill skip"/"parfillleftskip", so I'm not too
sure what to do to avoid this warning.
You can reproduce the warning with this code (but any call to
"tex.linebreak" also works):
\startluacode
function test(head)
tex.linebreak(node.copylist(head))
return head
end
nodes.tasks.appendaction("processors", "after", "test")
\stopluacode
\starttext
Hello!
\stoptext
2. The LuaMetaTeX manual says that "pre_linebreak_filter" is called
after the parfillskip glue has been added, but this doesn't seem to
be the case. With LuaLaTeX/Plain LuaTeX, this is true, but the node
list passed to the callback in MkXL is missing the parfillskip. (I
don't have an MkIV installation to test here.)
This MkXL code:
\startluacode
function test(head)
local last = node.slide(head)
print "START"
for i=1,3 do
print(last)
print(
node.type(last.id),
node.subtypes(last.id)[last.subtype],
last.width,
last.stretchorder,
last.stretch
)
last = last.prev
end
print "STOP"
return head
end
nodes.tasks.appendaction("processors", "after", "test")
\stopluacode
\starttext
Hello!
\stoptext
produces:
START
nil : glue spaceskip>
gluespaceskip 341648 0 384354
2258 : glyph unset>
glyph nil 213792 nil nil
2521 : glyph unset>
glyph nil 385140 nil nil
STOP
START
nil : glue userskip>
glueuserskip0 2 65536
2357 : glyph unset>
glyph nil 385140 nil nil
2611 : rule strut>
rulestrut 0 nil nil
STOP
while this (presumably) equivalent Plain LuaTeX code:
\directlua{
function test(head)
local last = node.slide(head)
print "START"
for i=1,3 do
print(last)
print(
node.type(last.id),
node.subtypes(last.id)[last.subtype],
last.width,
last.stretch_order,
last.stretch
)
last = last.prev
end
print "STOP"
return head
end
callback.register("pre_linebreak_filter", test)
}
Hello!
\bye
produces:
START
nil : glue 15>
glueparfillskip 0 2 65536
298 : penalty 2>
penalty linepenalty nil nil nil
82 : glyph 0>
glyph unset 182045 nil nil
STOP
I'm not sure if this is a doc bug, an engine bug, or if I'm just
doing something wrong.
3. The LuaTeX/LuaMetaTeX engine manuals say that for node callbacks, you
can return "true" if you don't need to replace the passed node list.
This works fine with raw LuaTeX callbacks and the luatexbase
wrappers, but it doesn't work with the ConTeXt "nodes.tasks" wrapper
functions.
This Plain example works:
\directlua{
callback.register("pre_linebreak_filter", function ()
return true
end)
}
Hello!
\bye
But this MkXL example doesn't:
\startluacode
function test(head)
return true
end
nodes.tasks.appendaction("processors", "after", "test")
\stopluacode
\starttext
Hello!
\stoptext
I'm not sure if this behaviour is expected or not. Saving the node
passed to the callback then
Re: [NTG-context] recursion in a table
On Sun, 1 May 2022, Henning Hraban Ramm via ntg-context wrote:
> Hi,
> I was playing with the example from
> https://wiki.contextgarden.net/Scaling_Rotating_Mirroring_Clipping#Location_parameter
>
> and tried to put it in a tabulate:
>
>
> \useMPlibrary[dum]
> \setupexternalfigures[width=3em,height=2em,frame=on,]
>
> %\def\TXT{\ruledhbox{\bf(XyX)}}
> \def\TXT{\externalfigure[pic]}
>
> \starttabulate[|l|l|l|l|l|l|]
> \NC\NC normal\NC depth\NC fit\NC broad\NC high\NC\NR
> \HL
> \dostepwiserecurse{0}{359}{45}{%
> %\expanded{\setuprotate[rotation=\recurselevel]}
> \NC{\expanded{\recurselevel}˚}%
Untested, but I think that you might need:
\expanded{\NC \recurselevel \noexpand\NC ... }
> This works, but \recurselevel is always 0. I know I must expand it (like
> in the original example), but I can’t make it work within the tabulation.
> In the first column, \expanded{\recurselevel} stays 0, and
> rotation=\expanded{\recurselevel} gives an error, while the \setuprotate
> line has no effect (if I remove "rotation=\recurselevel", of course).
>
> How would that work?
Remind me of a more-than-a-decade-old discussion on the mailing list,
summarized here:
https://adityam.github.io/context-blog/post/tex-programming/
> Also, \HL doesn’t work at the end, and the second line of the error
> message makes no sense:
I find that in such cases, using Lua (CLD) is the simplest solution
Aditya___
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[NTG-context] recursion in a table
Hi,
I was playing with the example from
https://wiki.contextgarden.net/Scaling_Rotating_Mirroring_Clipping#Location_parameter
and tried to put it in a tabulate:
\useMPlibrary[dum]
\setupexternalfigures[width=3em,height=2em,frame=on,]
%\def\TXT{\ruledhbox{\bf(XyX)}}
\def\TXT{\externalfigure[pic]}
\starttabulate[|l|l|l|l|l|l|]
\NC\NC normal\NC depth\NC fit\NC broad\NC high\NC\NR
\HL
\dostepwiserecurse{0}{359}{45}{%
%\expanded{\setuprotate[rotation=\recurselevel]}
\NC{\expanded{\recurselevel}˚}%
\NC{\ruledhbox{X\rotate[location=normal,rotation=\recurselevel]{\TXT}X}}%
\NC{\ruledhbox{X\rotate[location=depth,rotation=\recurselevel]
{\TXT}X}}%
\NC{\ruledhbox{X\rotate[location=fit,rotation=\recurselevel]
{\TXT}X}}%
\NC{\ruledhbox{X\rotate[location=broad,rotation=\recurselevel]
{\TXT}X}}%
\NC{\ruledhbox{X\rotate[location=high,rotation=\recurselevel]
{\TXT}X}}%
\NC\NR}
%\HL % error
\stoptabulate
This works, but \recurselevel is always 0. I know I must expand it (like
in the original example), but I can’t make it work within the tabulation.
In the first column, \expanded{\recurselevel} stays 0, and
rotation=\expanded{\recurselevel} gives an error, while the \setuprotate
line has no effect (if I remove "rotation=\recurselevel", of course).
How would that work?
Also, \HL doesn’t work at the end, and the second line of the error
message makes no sense:
"""
I expect to see \noalign only after the \cr of an alignment.
Proceed, and I'll ignore this case.
mtx-context | fatal error: return code: 1
"""
Hraban
___
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webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___
Re: [NTG-context] Fuzzy paragraph when exporting to XML
On 5/1/2022 12:17 AM, Aditya Mahajan via ntg-context wrote:
On Sat, 30 Apr 2022, Hans Hagen via ntg-context wrote:
On 4/29/2022 4:59 PM, Aditya Mahajan via ntg-context wrote:
Hi,
I am trying to debug a bug-report for t-vim:
https://github.com/adityam/filter/issues/64 Exporting with trackers=export*
gives a warning:
backend > export > fuzzy paragraph:
I have managed to narrow it down to the attached MWE (which does not depend
on the t-vim module at all). Compiling it using
$context --trackers=export\* lines
gives the fuzzy paragraph warning. Any hints on how to resolve this?
As you like challenges ... you can way more narrow it down ...
\setupbackend[export=yes]
\starttext
{
\forgetall
% \forgeteverypar
x\strut\par
}
\stoptext
the problem is that you basically loose *all* par related tagging now so
you need to bring that back, which is (of course i had to look it up) is
done with for instance \forgeteverypar which forgets (as in \forgetall)
but not really all
Thanks!
I manually tag start and end of lines anyways (using \SYNBOL ... \SYNEOL), so I
can add \dotagsetparcounter in \SYNBOL and that removes the warning!
dangerous ... what if you get
every line cna be a par or the while can have the same par number ...
these par numbers are used to determine what text belongs to a
meanignful something
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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___
[NTG-context] 32-bit OpenBSD
Hi, How long do we want/need to keep running the builders for 32-bit OpenBSD? It's taking 2 or 3 times longer to build binaries than for the 64-bit OS (not that this is super relevant since ppc builder is a whole order of magnitude slower anyway: building TL there takes about 6 hours) and I suspect that nobody is using those 32-bit binaries anyway. Mojca ___ 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 webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___
