Bug#827740: isympy start fails: No module named sympy.interactive

[Alberto Luaces]

Francesco Poli writes:

> Yes, that's why I suggested you to install python-sympy.
>

I do not want to do that :)  I want to use python3.

>
> You can also keep python3-sympy installed, if you like (in case you
> want to load the sympy module from python3), but isympy is a script
> designed to be interpreted by /usr/bin/python, which is Python v2.7.x
> and not v3.x ...
>

There is were we disagree.  From the description of the package and its
dependencies, it is not said that it is exclusive for python2.

>
> I don't know whether there is an elegant way to make isympy
> automatically figure out whether you would prefer using python or
> python3.
>

[...]

>
> Maybe another binary package could be added (named isympy3), including
> an appropriate isympy3 script...
> At that point isympy would depend on python-sympy (without
> python3-sympy as an alternative dependency) and isympy3 would depend on
> python3-sympy.

I guess a good solution could be one along the lines you are posting:
having two packages with no intermixed dependencies, with some aid of
the dpkg alternative system (that is used, for example, to set the
default version of gcc).  Unfortunately, I currently do not know enough
of that system in order to send a patch right now.

Francesco, thanks for your help and sorry for my stubbornness, but I
want to make clear that this is a bug, although for sure it can be
overcome by tinkering.