[NTG-context] Xml filtering in Lua

[denis.maier at unibe.ch]

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 at ntg.nl> Im Auftrag von mf via ntg-
> context
> Gesendet: Mittwoch, 16. November 2022 20:56
> An: ntg-context at ntg.nl
> Cc: mf <massifr at 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
> 
> __________________________________________________________
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> -----Ursprüngliche Nachricht-----
> Von: ntg-context <ntg-context-bounces at 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 at ntg.nl>
> Cc: Thomas A. Schmitz <thomas.schmitz at 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 at 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
> __________________________________________________________
> _________________________