# [NTG-context] runtime problem with metafun() code

Hans Hagen pragma at wxs.nl
Sat Jan 25 01:07:22 CET 2014

On 1/24/2014 7:41 PM, Peter Rolf wrote:
> Am 24.01.2014 14:45, schrieb Hans Hagen:
>> On 1/24/2014 1:35 PM, Peter Rolf wrote:
>>> Hi,
>>>
>>> I try to create a Metapost path in lua and it works so far for the
>>> attached example. But a call of that function from another lua function
>>> sadly fails (no path visible after call). The code seems to be executed
>>> later (the output from 'show pid;' appears somewhere later in the log).
>>>
>>> How can I ensure that the code is executed at runtime?
>>
>> I don't understand the issue but isn't there a
>>
>>      metafun("draw p;")
>>
>> missing then?
>>
> Setting the bounding box has the same effect, as drawing something.
> Both methods avoid that the emtpy graphic is ignored by ConTeXt.
>
> Anyhow, the MP path is not available in metapost.variables after the
> function call. If there is no other way I have to call the function from
> the TeX side (like in the attached example). Will look into that tomorrow.

%D We also provide an outputless run:

\unexpanded\def\startMPcalculation

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