Tobias Geerinckx-Rice <m...@tobias.gr> skribis:
> On 2016-07-21 18:06, l...@gnu.org wrote:
>>>> (inputs `(("somethingsilly" ,glib "bin")))
>>
>> This "somethingsilly" is just a label that allows you to refer to an
>> input on the build side, in idioms like:
>>
>> (assoc-ref inputs "somethingsilly")
>> => "/gnu/store/…-glib-42.0-bin"
>
> I remember writing something like
>
> (inputs `(("libuuid" ,util-linux)))
>
> once, to indicate that libuuid really is all we need and that one
> could swap out util-linux for another — extremely hypothetical —
> libuuid provider.
>
> Was this, in hindsight, somethingsilly? :-)
I think it’s fine, but a comment would work well too.
> If so, is there still a reason to keep all this duplication around?
Build systems haven’t migrated yet to gexps. There’s a branch to do
that, ‘wip-build-systems-gexp’, but there’s a performance regression
compared to what we have, which is why I have not merged it.
That’ll happen, someday, but even then, I’m not sure we’ll remove
labels; at least we won’t remove them overnight, for sure. ;-)
>> This predates g-expressions, which solve this problem more elegantly.
>
> Interesting! I always assumed[1] gexps were one of the foundations for
> Guix since day 0.
In an ideal world it would have been this way. :-)
Ludo’.
