From: Hans Hagen <j.hagen@xs4all.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>,
Otared Kavian <otared@gmail.com>
Subject: Re: How to use in Metafun, a function defined in Lua
Date: Sat, 28 Dec 2019 16:46:15 +0100 [thread overview]
Message-ID: <dfc6353e-4ba6-9979-326d-0d6d5b096844@xs4all.nl> (raw)
In-Reply-To: <F0146DF6-8A04-42B7-90BC-E0FE92D1445F@gmail.com>
On 12/28/2019 4:22 PM, Otared Kavian wrote:
> Hi all,
>
> I would like to use a math function defined in lua in Metafun in order to draw its graph, together with the graphs of some other functions.
> As a simple example consider the following:
>
> %%% begin lua-metafun-example.tex
> \startluacode
> function document.myfunction(n,x)
> local S
> S = math.sin(n*x)
> return S
> end
> \stopluacode
>
> \starttext
>
> Here \type{document.myfunction(n,x)} is $\sin(nx)$. For instance when $n = 2$ and $x = 355/113$ we have:
>
> \type{document.myfunction(2,355/113)} $=\cldcontext{document.myfunction(2,355/113)} \sim 0$.
>
> \startplacefigure[title={Nothing works\dots}]
> \startMPcode{GridAxis}
> numeric gu ; gu = 5mm ; % gu = graph unit
> draw image (
> draw function (1,"x","document.myfunction(2,x)", % <-- this does not work
> % draw function (1,"x","sin(2*x)", % <-- this works
> -355/113,355/113,.01)
> scaled gu
> withpen pencircle scaled .075pt
> withcolor darkred ;
> ) xsized .7TextWidth ;
> \stopMPcode
> \stopplacefigure
>
> \stoptext
> %%% end lua-metafun-example.tex
>
> Here one sees that the function « document.myfunction » is well defined in Lua and is known in ConTeXt, but I cannot use it in a Metapost code: how can one do that?
you confuse lua and mp functions
\startluacode
function MP.myfunction(n,x)
return math.sin(n*x)
end
\stopluacode
\starttext
\startMPcode
numeric gu ; gu = 5mm ;
vardef myfunction(expr n, x) = MP.myfunction(n,x) enddef ;
draw image (
draw function (1,"x","myfunction(2,x)",-355/113,355/113,.01)
scaled gu
withpen pencircle scaled .075pt
withcolor darkred ;
) xsized .7TextWidth ;
\stopMPcode
\stoptext
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prev parent reply other threads:[~2019-12-28 15:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-28 15:22 Otared Kavian
2019-12-28 15:46 ` Hans Hagen [this message]
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