Here in Terminal on my Mac:

21 ~: lua
Lua 5.4.6  Copyright (C) 1994-2023 Lua.org, PUC-Rio
> string.gsub('a%20b', '%%20', ' ')
a b	1
> (string.gsub('a%20b', '%%20', ' '))
a b
> ^D
21 ~: 

The first call returns the 1 giving the match, the extra ()'s get rid of that second return value.

yours sincerely
dr. Hans van der Meer



> On 21 Jul 2023, at 12:37, denis.maier@unibe.ch wrote:
> 
> Hi,
>  
> I’m typesetting an XML document where the links to the images contain spaces which are encoded as %20
> <graphic xlink:href="a%20filename%20with%20spaces.jpg"/>
>  
> Using this works in cases without spaces:
>  
> \startxmlsetups xml:fig:graphic
>   \externalfigure[\xmlatt{#1}{xlink:href}]
> \stopxmlsetups
>  
> This also works for normal spaces, but is there a way to decode/expand the %20s to regular spaces?
>  
> I’ve tried with some Lua, but I don’t really know how to pass data around.
>  
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> \startluacode
> function replaceSpaces(s)
>   result = string.gsub(s, "%%20", " ")
>   context(result)
> end
> \stopluacode
>  
> \define[1]\replaceSpaces{\ctxlua{replaceSpaces("#1")}}
>  
> \startxmlsetups xml:fig:graphic
>   \externalfigure[\replaceSpaces{\xmlatt{#1}{xlink:href}}]
> \stopxmlsetups
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>  
> Any hints, why this does not work?`
>  
> Also, maybe there’s a simpler way for this kind of scenario?
> 
> Best,
> Denis
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