Hi,

Thanks for your inputs Aditya and Bruce.

I’m still having some issues when trying to include the output of the filter module within lua.

MNWE:

\defineexternalfilter
 [sympy]
 [filtercommand={/Users/aleks/miniconda3/bin/python3 \externalfilterinputfile\space > \externalfilteroutputfile},
 bufferbefore=init,
 output={\externalfilterbasefile.out},
 readcommand=\typefile,
 read=no,]

\startbuffer[init]
from sympy import *
\stopbuffer

\starttext

\startluacode
 local deg2rad = [[
 %\startsympy

 print(latex(rad(%angleVal%)))
 %\stopsympy
	]]

	local calcTrigFunction = [[
 \startsympy
 from sympy import *

 print(latex(%fname%(rad(%angleVal%))))
 \stopsympy
	]]

	local angleList = {0, 30, 45, 60, 90, 120, 135, 150, 180, 210, 225, 240, 270, 300, 315, 330, 360}

	for _, a in ipairs(angleList) do
 context.templates[calcTrigFunction] {
 fname = "sin",
 angleVal = a
 }
	end

\stopluacode

\stoptext

In particular, it fails as soon as  \startsympy and \stopsympy are part of the template. Should I protect these?

A. Christe
Le 25 oct. 2023 à 21:56 +0200, Aditya Mahajan <adityam@umich.edu>, a écrit :
> On Wed, 25 Oct 2023, Alexandre Christe wrote:
>
> > Dear list,
> >
> > I’d like to know the best approach to make this a bit more usable. I’m trying to typeset a table with sin/cos/tan values. I’d like to be able to convert the angles in degrees into radians (with math notation) and to compute the trigonometric function leading to sin(pi/4) = 1/2, or cos(pi/6) = sqrt(3)/2 and display it in math mode.
> >
> > Here’s my current MWE, where I fail to convert the angles in radians
>
> there is math.sind, cosd, etc. for computing sin for angle in degrees. The implementation is l-math.lua is:
>
> local pipi = 2*math.pi/360
>
> function math.sind(d) return sin(d*pipi) end
> function math.cosd(d) return cos(d*pipi) end
> function math.tand(d) return tan(d*pipi) end
>
> > and fail to display the result in symbolic form.
>
> Context doesn't do symbolic math. You can try checking if one of the symbolic math libraries in lua provides all the features that you want.
>
> > One possible way would be to use Python and the t-filter module, like this
>
> This can work as follows. Take the array of angles, and convert them to the desired format in python and write them to a temp file. Read that temp file in lua and typeset it as you want.
>
> Another option is an old proof of concept by Luigi: https://github.com/bastibe/lunatic-python which allowed two-way communication between python and luatex. Not sure if it still works.
>
> Aditya
>
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