On Mon, 28 Jul 2014, Wolfgang Schuster wrote:

>
> Am 28.07.2014 um 16:15 schrieb Xan <dxpublica@telefonica.net>:
>
>> Hi,
>>
>> Any hint on that [https://github.com/adityam/filter/issues/17], please?
>
> Don’t use \doifmode{…}{…} etc. with buffers or environments which rely on a buffer because you disable the function to keep end of lines in the input.
>
> What you have to do in this case is to use the \startmode or \startnotmode commands.
>
> \usemodule[filter]
>
> \defineexternalfilter
>    [python]
>    [filtercommand={python \externalfilterinputfile\space > \externalfilteroutputfile},cache=force]
>
> \starttext
>
> \startmode[solucions]
>
> \starttextrule{Solucions}
>
> \startpython
> ....
> \stoppython
>
> \stoptextrule
>
> \stopmode
>
> \stoptext

Another option is (untested):

\defineexternalfilter
   [python]
   [
     filtercommand={...},
     before={\starttextrule{Solutions}},
     after={\stoptextrule},
   ]

\startmode[solutions]
\setupexternalfilter[python][state=stop, read=no]
\stopmode

\starttext

\startpython
...
\stoppython
\stoptext

BTW, you can simplify your setup using:

\startbuffer[sympy]
from sympy.solvers import solve
from sympy import Symbol
from sympy import Eq

x = Symbol('x')
\stopbuffer

\defineexternalfilter
   [python]
   [
     filtercommand={...},
     bufferbefore={sympy},
   ]

\starttext
\startpython
print(solve(Eq(3*x + 2, 35), x))
\stoppython
\stoptext

Aditya