Xml filtering in Lua

Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

Hi all,

I thought this was easy, but I overestimated my competence… I want to filter xml elements via their attributes and retrieve and typeset parts belonging together. Here is a small test file that explains what I’m trying:

\startbuffer[test]
<document>
   <topics>
      <topic id="test1">
	<title>This is the first test</title>
	<date>22/11/16</date>
      </topic>
      <topic id="test2">
	<title>This is the second test</title>
	<date>22/11/17</date>
      </topic>
   </topics>
   <chapters>
      <chapter id="test1">
	<content>
	  This will be the content of the <emph>first</emph> chapter.
	</content>
      </chapter>
      <chapter id="test2">
	 <content>
	  This will be the content of the <emph>second</emph> chapter.
	 </content>
      </chapter>
   </chapters>
</document>
\stopbuffer

\startxmlsetups xml:testsetups
        \xmlsetsetup{#1}{*}{-}
	\xmlsetsetup{#1}{document|chapters|chapter|content|emph}{xml:*}
\stopxmlsetups

\xmlregistersetup{xml:testsetups}

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

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

\startxmlsetups xml:chapter
	\xmlfunction {#1} {chapter}
	 \xmlflush {#1}	
\stopxmlsetups

\startxmlsetups xml:chapter:content
	\xmltext {#1} {content}
\stopxmlsetups

\startxmlsetups xml:emph
   {\em \xmlflush {#1}}
\stopxmlsetups

\startluacode
function xml.functions.chapter (t)
	 local ch_id = t.at.id
		local metadata = xml.filter (root, '../../topics/topic[@id=="%s"]', ch_id)
		print (inspect(metadata))
		lxml.command(t, ".", "xml:chapter:content")
		context.par ()
		context (ch_id)
		context.par ()
end
\stopluacode

\starttext
	\xmlprocessbuffer{main}{test}{}
\stoptext

The line with xml.filter does not work as I expected. How can I walk the tree, find the “topic” element with the same “id” attribute as the chapter I’m currently in, and then typeset the different children of the topic element? 

Thanks a lot and all best

Thomas

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___________________________________________________________________________________

Re: Xml filtering in Lua

[Duncan Hothersall via ntg-context]

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Hi Thomas.

I'm not sure about the code, sorry, but I do know that an XML document
can't have two IDs of the same value. Typically you would use a linkend
attribute on the element which is referencing an id (in this case the
topics, I think).

Probably doesn't help with your problem, but it's likely a prerequisite for
it to work.

Bests,

Duncan

On Wed, 16 Nov 2022 at 16:11, Thomas A. Schmitz via ntg-context <
ntg-context@ntg.nl> wrote:

> Hi all,
>
> I thought this was easy, but I overestimated my competence… I want to
> filter xml elements via their attributes and retrieve and typeset parts
> belonging together. Here is a small test file that explains what I’m trying:
>
> \startbuffer[test]
> <document>
>    <topics>
>       <topic id="test1">
>         <title>This is the first test</title>
>         <date>22/11/16</date>
>       </topic>
>       <topic id="test2">
>         <title>This is the second test</title>
>         <date>22/11/17</date>
>       </topic>
>    </topics>
>    <chapters>
>       <chapter id="test1">
>         <content>
>           This will be the content of the <emph>first</emph> chapter.
>         </content>
>       </chapter>
>       <chapter id="test2">
>          <content>
>           This will be the content of the <emph>second</emph> chapter.
>          </content>
>       </chapter>
>    </chapters>
> </document>
> \stopbuffer
>
> \startxmlsetups xml:testsetups
>         \xmlsetsetup{#1}{*}{-}
>         \xmlsetsetup{#1}{document|chapters|chapter|content|emph}{xml:*}
> \stopxmlsetups
>
> \xmlregistersetup{xml:testsetups}
>
> \startxmlsetups xml:document
>         \xmlflush{#1}
> \stopxmlsetups
>
> \startxmlsetups xml:chapters
>         \xmlflush{#1}
> \stopxmlsetups
>
> \startxmlsetups xml:chapter
>         \xmlfunction {#1} {chapter}
>          \xmlflush {#1}
> \stopxmlsetups
>
> \startxmlsetups xml:chapter:content
>         \xmltext {#1} {content}
> \stopxmlsetups
>
> \startxmlsetups xml:emph
>    {\em \xmlflush {#1}}
> \stopxmlsetups
>
> \startluacode
> function xml.functions.chapter (t)
>          local ch_id = t.at.id
>                 local metadata = xml.filter (root,
> '../../topics/topic[@id=="%s"]', ch_id)
>                 print (inspect(metadata))
>                 lxml.command(t, ".", "xml:chapter:content")
>                 context.par ()
>                 context (ch_id)
>                 context.par ()
> end
> \stopluacode
>
> \starttext
>         \xmlprocessbuffer{main}{test}{}
> \stoptext
>
> The line with xml.filter does not work as I expected. How can I walk the
> tree, find the “topic” element with the same “id” attribute as the chapter
> I’m currently in, and then typeset the different children of the topic
> element?
>
> Thanks a lot and all best
>
> Thomas
>
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to
> the Wiki!
>
> maillist : ntg-context@ntg.nl /
> https://www.ntg.nl/mailman/listinfo/ntg-context
> webpage  : https://www.pragma-ade.nl / http://context.aanhet.net
> archive  : https://bitbucket.org/phg/context-mirror/commits/
> wiki     : https://contextgarden.net
>
> ___________________________________________________________________________________
>

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

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wiki     : https://contextgarden.net
___________________________________________________________________________________

Re: Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

Hi Duncan,

Thank you for pointing this out! I knew this was true inside the xmlns namespace, so you can’t have identical xml:id tags, but you’re probably right that it’s better to avoid this confusion altogether. Alas, this doesn’t help with my problem. Since there was a type in my minimal example from my experimentations, I include a corrected version, avoiding the identical tags

All best

Thomas

\startbuffer[test]
<document>
  <topics>
     <topic t:id="test1">
	<title>This is the first test</title>
	<date>22/11/16</date>
     </topic>
     <topic t:id="test2">
	<title>This is the second test</title>
	<date>22/11/17</date>
     </topic>
  </topics>
  <chapters>
     <chapter ch:id="test1">
	<content>
	  This will be the content of the <emph>first</emph> chapter.
	</content>
     </chapter>
     <chapter ch:id="test2">
	 <content>
	  This will be the content of the <emph>second</emph> chapter.
	 </content>
     </chapter>
  </chapters>
</document>
\stopbuffer

\startxmlsetups xml:testsetups
       \xmlsetsetup{#1}{*}{-}
	\xmlsetsetup{#1}{document|chapters|chapter|content|emph}{xml:*}
\stopxmlsetups

\xmlregistersetup{xml:testsetups}

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

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

\startxmlsetups xml:chapter
	\xmlfunction {#1} {chapter}
	 \xmlflush {#1}	
\stopxmlsetups

\startxmlsetups xml:chapter:content
	\xmltext {#1} {content}
\stopxmlsetups

\startxmlsetups xml:emph
  {\em \xmlflush {#1}}
\stopxmlsetups

\startluacode
function xml.functions.chapter (t)
	 local ch_id = t.at.ch:id
		local metadata = xml.filter (t, '../../topics/topic[@t:id=="%s"]', ch_id)
		print (inspect(metadata))
		lxml.command(t, ".", "xml:chapter:content")
		context.par ()
		context (ch_id)
		context.par ()
end
\stopluacode


> On 16. Nov 2022, at 17:18, Duncan Hothersall via ntg-context <ntg-context@ntg.nl> wrote:
> 
> I'm not sure about the code, sorry, but I do know that an XML document can't have two IDs of the same value. Typically you would use a linkend attribute on the element which is referencing an id (in this case the topics, I think).
> 
> Probably doesn't help with your problem, but it's likely a prerequisite for it to work.
> 
> Bests,
> 
> Duncan


___________________________________________________________________________________
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___________________________________________________________________________________

Re: Xml filtering in Lua

[mf via ntg-context]

Il 16/11/22 18:33, Thomas A. Schmitz via ntg-context ha scritto:
> \startbuffer[test]
> <document>
>    <topics>
>       <topic t:id="test1">
> 	<title>This is the first test</title>
> 	<date>22/11/16</date>
>       </topic>
>       <topic t:id="test2">
> 	<title>This is the second test</title>
> 	<date>22/11/17</date>
>       </topic>
>    </topics>
>    <chapters>
>       <chapter ch:id="test1">
> 	<content>
> 	  This will be the content of the <emph>first</emph> chapter.
> 	</content>
>       </chapter>
>       <chapter ch:id="test2">
> 	 <content>
> 	  This will be the content of the <emph>second</emph> chapter.
> 	 </content>
>       </chapter>
>    </chapters>
> </document>
> \stopbuffer
>
> \startxmlsetups xml:testsetups
>         \xmlsetsetup{#1}{*}{-}
> 	\xmlsetsetup{#1}{document|chapters|chapter|content|emph}{xml:*}
> \stopxmlsetups
>
> \xmlregistersetup{xml:testsetups}
>
> \startxmlsetups xml:document
> 	\xmlflush{#1}
> \stopxmlsetups
>
> \startxmlsetups xml:chapters
> 	\xmlflush{#1}
> \stopxmlsetups
>
> \startxmlsetups xml:chapter
> 	\xmlfunction {#1} {chapter}
> 	 \xmlflush {#1}	
> \stopxmlsetups
>
> \startxmlsetups xml:chapter:content
> 	\xmltext {#1} {content}
> \stopxmlsetups
>
> \startxmlsetups xml:emph
>    {\em \xmlflush {#1}}
> \stopxmlsetups
>
> \startluacode
> function xml.functions.chapter (t)
> 	 local ch_id = t.at.ch:id


local ch_id = t.at["ch:id"]


> 		local metadata = xml.filter (t, '../../topics/topic[@t:id=="%s"]', ch_id)
> 		print (inspect(metadata))
> 		lxml.command(t, ".", "xml:chapter:content")
> 		context.par ()
> 		context (ch_id)
> 		context.par ()
> end
> \stopluacode

Best wishes,

Massi

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

maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________

Re: Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

On 11/16/22 19:56, mf via ntg-context wrote:
> local ch_id = t.at["ch:id"]

You're right, of course, using a colon was a stupid idea. When I replace 
it with an underscore, you can see that both are in fact identical:

\startbuffer[test]
<document>
   <topics>
      <topic t_id="test1">
	<title>This is the first test</title>
	<date>22/11/16</date>
      </topic>
      <topic t_id="test2">
	<title>This is the second test</title>
	<date>22/11/17</date>
      </topic>
   </topics>
   <chapters>
      <chapter ch_id="test1">
	<content>
	  This will be the content of the <emph>first</emph> chapter.
	</content>
      </chapter>
      <chapter ch_id="test2">
	 <content>
	  This will be the content of the <emph>second</emph> chapter.
	 </content>
      </chapter>
   </chapters>
</document>
\stopbuffer

\startxmlsetups xml:testsetups
        \xmlsetsetup{#1}{*}{-}
	\xmlsetsetup{#1}{document|chapters|chapter|content|emph}{xml:*}
\stopxmlsetups

\xmlregistersetup{xml:testsetups}

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

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

\startxmlsetups xml:chapter
	\xmlfunction {#1} {chapter}
%	 \xmlflush {#1}	
\stopxmlsetups

\startxmlsetups xml:chapter:content
	\xmltext {#1} {content}
\stopxmlsetups

\startxmlsetups xml:emph
   {\em \xmlflush {#1}}
\stopxmlsetups

\startluacode
function xml.functions.chapter (t)
	 local chapter_id = t.at.ch_id
	 local other_chapter_id = t.at["ch_id"]
	 context (chapter_id)
	 context.par ()
	 context (other_chapter_id)
	 context.par ()
		local metadata = xml.filter (t, '../../topics/topic[@t:id=="%s"]', ch_id)
		print (inspect(metadata))
		lxml.command(t, ".", "xml:chapter:content")
		context.par ()
end
\stopluacode

\starttext
	\xmlprocessbuffer{main}{test}{}
\stoptext

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

maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : https://www.pragma-ade.nl / http://context.aanhet.net
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wiki     : https://contextgarden.net
___________________________________________________________________________________

Re: Xml filtering in Lua

[Denis Maier via ntg-context]

Just a quick question regarding this?
Is xml.filter equivalent to \xmlfilter? If so, how do you pass the match to a command as you'd do with \xmlfilter?

Best,
Denis

> -----Ursprüngliche Nachricht-----
> Von: ntg-context <ntg-context-bounces@ntg.nl> Im Auftrag von mf via ntg-
> context
> Gesendet: Mittwoch, 16. November 2022 20:56
> An: ntg-context@ntg.nl
> Cc: mf <massifr@fastwebnet.it>
> Betreff: Re: [NTG-context] Xml filtering in Lua
> 
> This works:
> 
> local metadata = xml.filter (t, '../../topics/topic[@t:id=="' .. ch_id .. '"]')
> 
> also this:
> 
> local lpath = string.format('../../topics/topic[@t:id=="%s"]', ch_id)
> 
> local metadata = xml.filter (t, lpath)
> 
> 
> It looks like xml.filter supports only 2 arguments (see lxml-tex.lua), and so it
> doesn't let you use string formatting patterns like the "context" command
> does.
> 
> You can write:
> 
> context('the value of @t:id is "%s"', ch_id)
> 
> but you can't write:
> 
> xml.filter (t, '../../topics/topic[@t:id=="%s"]', ch_id)
> 
> 
> Best wishes,
> 
> Massi
> 
> __________________________________________________________
> _________________________
> If your question is of interest to others as well, please add an entry to the
> Wiki!
> 
> maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-
> context
> webpage  : https://www.pragma-ade.nl / http://context.aanhet.net archive
> : https://bitbucket.org/phg/context-mirror/commits/
> wiki     : https://contextgarden.net
> __________________________________________________________
> _________________________

> -----Ursprüngliche Nachricht-----
> Von: ntg-context <ntg-context-bounces@ntg.nl> Im Auftrag von Thomas A.
> Schmitz via ntg-context
> Gesendet: Mittwoch, 16. November 2022 20:56
> An: mailing list for ConTeXt users <ntg-context@ntg.nl>
> Cc: Thomas A. Schmitz <thomas.schmitz@uni-bonn.de>
> Betreff: Re: [NTG-context] Xml filtering in Lua
> 
> On 11/16/22 19:56, mf via ntg-context wrote:
> > local ch_id = t.at["ch:id"]
> 
> You're right, of course, using a colon was a stupid idea. When I replace it with
> an underscore, you can see that both are in fact identical:
> 
> \startbuffer[test]
> <document>
>    <topics>
>       <topic t_id="test1">
> 	<title>This is the first test</title>
> 	<date>22/11/16</date>
>       </topic>
>       <topic t_id="test2">
> 	<title>This is the second test</title>
> 	<date>22/11/17</date>
>       </topic>
>    </topics>
>    <chapters>
>       <chapter ch_id="test1">
> 	<content>
> 	  This will be the content of the <emph>first</emph> chapter.
> 	</content>
>       </chapter>
>       <chapter ch_id="test2">
> 	 <content>
> 	  This will be the content of the <emph>second</emph> chapter.
> 	 </content>
>       </chapter>
>    </chapters>
> </document>
> \stopbuffer
> 
> \startxmlsetups xml:testsetups
>         \xmlsetsetup{#1}{*}{-}
> 	\xmlsetsetup{#1}{document|chapters|chapter|content|emph}{xml:
> *}
> \stopxmlsetups
> 
> \xmlregistersetup{xml:testsetups}
> 
> \startxmlsetups xml:document
> 	\xmlflush{#1}
> \stopxmlsetups
> 
> \startxmlsetups xml:chapters
> 	\xmlflush{#1}
> \stopxmlsetups
> 
> \startxmlsetups xml:chapter
> 	\xmlfunction {#1} {chapter}
> %	 \xmlflush {#1}
> \stopxmlsetups
> 
> \startxmlsetups xml:chapter:content
> 	\xmltext {#1} {content}
> \stopxmlsetups
> 
> \startxmlsetups xml:emph
>    {\em \xmlflush {#1}}
> \stopxmlsetups
> 
> \startluacode
> function xml.functions.chapter (t)
> 	 local chapter_id = t.at.ch_id
> 	 local other_chapter_id = t.at["ch_id"]
> 	 context (chapter_id)
> 	 context.par ()
> 	 context (other_chapter_id)
> 	 context.par ()
> 		local metadata = xml.filter (t, '../../topics/topic[@t:id=="%s"]',
> ch_id)
> 		print (inspect(metadata))
> 		lxml.command(t, ".", "xml:chapter:content")
> 		context.par ()
> end
> \stopluacode
> 
> \starttext
> 	\xmlprocessbuffer{main}{test}{}
> \stoptext
> 
> __________________________________________________________
> _________________________
> If your question is of interest to others as well, please add an entry to the
> Wiki!
> 
> maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-
> context
> webpage  : https://www.pragma-ade.nl / http://context.aanhet.net archive
> : https://bitbucket.org/phg/context-mirror/commits/
> wiki     : https://contextgarden.net
> __________________________________________________________
> _________________________
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : https://www.pragma-ade.nl / http://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : https://contextgarden.net
___________________________________________________________________________________

Re: Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

On 11/16/22 21:51, Denis Maier via ntg-context wrote:
> Just a quick question regarding this?
> Is xml.filter equivalent to \xmlfilter? If so, how do you pass the match to a command as you'd do with \xmlfilter?

I'm still digesting and playing with Massi's reply; will probably be 
back with more questions :-)

Anyway:

If you've filtered something out like this

local tree = xml.filter (t, "../chapter[@title='mytitle'")

you can then apply a command to it

lxml.command(lxml.id(tree), ".", "xml:chapter:command")

and have to define the command as

\startxmlsetups xml:chapter:command
	\xmltext {#1} {content}
\stopxmlsetups

for example.

Thomas

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

Re: Xml filtering in Lua

[Hans Hagen via ntg-context]

On 11/16/2022 10:09 PM, Thomas A. Schmitz via ntg-context wrote:
> On 11/16/22 21:51, Denis Maier via ntg-context wrote:
>> Just a quick question regarding this?
>> Is xml.filter equivalent to \xmlfilter? If so, how do you pass the 
>> match to a command as you'd do with \xmlfilter?
> 
> I'm still digesting and playing with Massi's reply; will probably be 
> back with more questions :-)
> 
> Anyway:
> 
> If you've filtered something out like this
> 
> local tree = xml.filter (t, "../chapter[@title='mytitle'")

always keep in mind that some expressions return a list of matches, that 
can be looped over and some commands just process the first

anyway, it can sometimes help to add

print(tstring(tree))

so see what you got

Hans

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               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
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___________________________________________________________________________________
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___________________________________________________________________________________

Re: Xml filtering in Lua

[mf via ntg-context]

This works:

local metadata = xml.filter (t, '../../topics/topic[@t:id=="' .. ch_id 
.. '"]')

also this:

local lpath = string.format('../../topics/topic[@t:id=="%s"]', ch_id)

local metadata = xml.filter (t, lpath)


It looks like xml.filter supports only 2 arguments (see lxml-tex.lua), 
and so it doesn't let you use string formatting patterns like the 
"context" command does.

You can write:

context('the value of @t:id is "%s"', ch_id)

but you can't write:

xml.filter (t, '../../topics/topic[@t:id=="%s"]', ch_id)


Best wishes,

Massi

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

maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : https://www.pragma-ade.nl / http://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : https://contextgarden.net
___________________________________________________________________________________

Re: Xml filtering in Lua

[Hans Hagen via ntg-context]

On 11/16/2022 8:56 PM, mf via ntg-context wrote:
> This works:
> 
> local metadata = xml.filter (t, '../../topics/topic[@t:id=="' .. ch_id 
> .. '"]')
> 
> also this:
> 
> local lpath = string.format('../../topics/topic[@t:id=="%s"]', ch_id)
> 
> local metadata = xml.filter (t, lpath)
> 
> 
> It looks like xml.filter supports only 2 arguments (see lxml-tex.lua), 
> and so it doesn't let you use string formatting patterns like the 
> "context" command does.
> 
> You can write:
> 
> context('the value of @t:id is "%s"', ch_id)
> 
> but you can't write:
> 
> xml.filter (t, '../../topics/topic[@t:id=="%s"]', ch_id)
In Thomas example this is also an approach:

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

with

\startluacode
local topics   = { }
local chapters = { }

function xml.functions.document(t)
     for c in xml.collected(t,"/topics/topic") do
         topics[c.at.t_id] = c
     end
  -- for c in xml.collected(t,"/chapters/chapter") do
  --     chapters[c.at.ch_id] = c
  --     -- or flush here
  -- end
end

function xml.functions.chapter (t)
     local ch_id = t.at.ch_id
     local metadata = topics[ch_id]
     lxml.command(t, ".", "xml:chapter:content")
     context.par ()
     context (ch_id)
     context.par ()
end
\stopluacode

so, basically you collect data and use it later ... for huge datasets 
that saves some time

if you have only chapters to process you can even decide to flush in 
that function

Hans

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                                           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: Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

> On 17. Nov 2022, at 11:04, Hans Hagen via ntg-context <ntg-context@ntg.nl> wrote:
> 
> so, basically you collect data and use it later ... for huge datasets that saves some time
> 
> if you have only chapters to process you can even decide to flush in that function
> 
> Hans

I think this is exactly the approach I’m looking for: collecting everything in Lua tables and then retrieving and typesetting it later. I’m experimenting with it right now. I will have to define a proper lxml.command for every xml tag, I guess; otherwise, the xml gets serialized? I’ll play some more and will certainly be back with questions :-)

Thank you, as always, and all best

Thomas
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Re: Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

On 11/17/22 11:04, Hans Hagen via ntg-context wrote:
> 
> so, basically you collect data and use it later ... for huge datasets 
> that saves some time
> 
> if you have only chapters to process you can even decide to flush in 
> that function

Alright, I'm making very good progress here, but right now I'm stumbling 
upon a problem I can't solve. It's difficult to make a minimal example, 
so bear with some snippets.

I load data from an external xml file (not the one I'm processing) and 
store some of it in a lua table.

local examples = lxml.load ("my_examples", "examples.xml")
local sets     = lxml.load ("my_sets", "example_sets.xml")

for e in xml.collected (examples, "/examples/chapter/example") do
	local ex_id = e.at.id
	all_examples [ex_id] = e
end

This works as expected, with print (inspect (all_examples)), I can see 
that the table looks the way I expect.

I then retrieve some entries of the table by their key:

local current_example = all_examples [key]

Again, this appears to work; when I have a

lxml.displayverbatim (current_example)

in my file, the xml is typeset and looks like I would expect it to look. 
However, whatever I try, I get the serialized xml typeset, with all 
<tags> verbatim, instead of processed. Here's what I've tried:

\startxmlsetups xml:chapter:example
	\xmlfirst {#1} {.} \par
\stopxmlsetups

lxml.command (current_example, ".", "xml:chapter:example")

or

xml.sprint (lxml.id (current_example))

or

local problem = xml.text (lxml.id (current_example), "./[text()]")
xml.sprint (problem)

I was expecting at least the last version to retrieve the pure text, but 
it typesets again with the tags included.

So I guess my question is: how can I tell ConTeXt to parse my xml as xml 
and apply the proper setups instead of serializing it?

All best wishes

Thomas
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Re: Xml filtering in Lua

[Thomas A. Schmitz via ntg-context]

On 11/20/22 19:19, Thomas A. Schmitz via ntg-context wrote:
> I load data from an external xml file (not the one I'm processing) and 
> store some of it in a lua table.
> 
> local examples = lxml.load ("my_examples", "examples.xml")

Replying to myself, and sorry for the noise (this was fairly easy, 
should have seen it earlier):

instead of loading the file "examples.xml," I simply include it via 
xmlinclude into the tree; this way the proper setups are applied.

All best

Thomas
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