* Passing macro parameters to lua
@ 2013-08-05 20:53 Matt Gushee
2013-08-05 21:00 ` Hans Hagen
0 siblings, 1 reply; 3+ messages in thread
From: Matt Gushee @ 2013-08-05 20:53 UTC (permalink / raw)
To: ConTeXt users' mailing list
Hello, good people--
I've encountered what appears to be a bug in either the TeX->Lua
interface or the documentation thereof (I have the latest stable
ConTeXt standalone from contextgarden.net).
I'm trying to create a macro that will insert different text depending
on whether one of the arguments is empty or not. My initial test
implementation (following the wiki section entitled "Passing arguments
and buffers: ConTeXt commands that hook into Lua") looked like this:
\startluacode
userdata = userdata or {}
function userdata.empty_or_not(str)
if str == "" or str == nil then
context("{\\sc Empty}")
else
context(str)
end
end
\stopluacode
\def\emptyOrNot#1{%
\ctxlua{userdata.empty_or_not(#1)}%
}
\starttext
\emptyOrNot{Amazing Text!}
\emptyOrNot{}
\stoptext
This did not work. I determined that even when I passed a non-empty
string, the Lua interpreter detected it as nil. It turns out the fix
was simple--I had to quote the string, as follows.
\def\emptyOrNot#1{%
\ctxlua{userdata.empty_or_not("#1")}%
}
It took me a while to figure that out, though, since the wiki example
does not show quotes.
--
Matt Gushee
___________________________________________________________________________________
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
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Passing macro parameters to lua
2013-08-05 20:53 Passing macro parameters to lua Matt Gushee
@ 2013-08-05 21:00 ` Hans Hagen
2013-08-05 21:35 ` Sietse Brouwer
0 siblings, 1 reply; 3+ messages in thread
From: Hans Hagen @ 2013-08-05 21:00 UTC (permalink / raw)
To: ntg-context
On 8/5/2013 10:53 PM, Matt Gushee wrote:
> Hello, good people--
>
> I've encountered what appears to be a bug in either the TeX->Lua
> interface or the documentation thereof (I have the latest stable
> ConTeXt standalone from contextgarden.net).
>
> I'm trying to create a macro that will insert different text depending
> on whether one of the arguments is empty or not. My initial test
> implementation (following the wiki section entitled "Passing arguments
> and buffers: ConTeXt commands that hook into Lua") looked like this:
>
> \startluacode
> userdata = userdata or {}
>
> function userdata.empty_or_not(str)
> if str == "" or str == nil then
> context("{\\sc Empty}")
> else
> context(str)
> end
> end
> \stopluacode
>
> \def\emptyOrNot#1{%
> \ctxlua{userdata.empty_or_not(#1)}%
> }
>
> \starttext
>
> \emptyOrNot{Amazing Text!}
>
> \emptyOrNot{}
>
> \stoptext
>
> This did not work. I determined that even when I passed a non-empty
> string, the Lua interpreter detected it as nil. It turns out the fix
> was simple--I had to quote the string, as follows.
>
> \def\emptyOrNot#1{%
> \ctxlua{userdata.empty_or_not("#1")}%
> }
>
> It took me a while to figure that out, though, since the wiki example
> does not show quotes.
indeed you need quotes
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
| www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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://tex.aanhet.net
archive : http://foundry.supelec.fr/projects/contextrev/
wiki : http://contextgarden.net
___________________________________________________________________________________
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