Re: Optional runtime dependencies in Guix

[ludo@gnu.org (Ludovic Courtès)]

Ricardo Wurmus <ricardo.wurmus@mdc-berlin.de> skribis:

> Ludovic Courtès writes:
>
>> Gammel Holte <gammel.holte@gmail.com> skribis:
>>
>>> For example, consider samtools, a package I use daily and that was recently
>>> committed to Guix:
>>>
>>> http://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/bioinformatics.scm#n139
>>>
>>> It forces me to install python. In contrast, consider Arch AUR's package:
>>>
>>> https://aur.archlinux.org/packages/samtools/
>>
>> From looking at the page above, it seems that it would be feasible to
>> simply move varfilter.py to a different output.  That way, users would
>> be able to install the default output (which doesn’t depend on Python),
>> or the “python” output.  Ricardo, WDYT?
>
> I could try to exclude this from the default output and install just the
> Python files in a separate "python" output.

Yes.

> Is there a way to specify inputs that are required by certain outputs
> only?  Then I could make the new "python" output depend on the Python
> package as an input.

There’s no way to do that.  So the build process would still depend on
Python.  However, someone using substitutes who does not want the Python
dependency would end up downloading just the Python-less output.

Thanks,
Ludo’.