Re: Recursively propagate build-system 'arguments' to dependency packages?

[Myles English]

Hello Fede, Eric,

on [2017-02-07] at 15:15 Federico Beffa writes:

> Eric Bavier <address@hidden> writes:
>
>> On Mon, 06 Feb 2017 21:09:33 +0000
>> Myles English <address@hidden> wrote:
>>
>>> Trying to define a package to be compiled by ghc-8, and I think all of
>>> its dependencies must also be compiled by ghc-8 rather than ghc (which
>>> is version 7).  This is easy to do with one package, e.g..:
>>>
>>> (define-module (my-packages myhaskell)
>>>  ...
>>>   #:use-module ((gnu packages haskell) #:prefix haskellmain:))
>>>
>>> (define-public ghc-hunit8
>>>   (package
>>>     (inherit haskellmain:ghc-hunit)
>>>     (arguments `(#:haskell ,ghc-8))))
>>>
>>> To do that recursively for all the dependencies seems Too Difficult so,
>>> is there a way to do something like --with-input=ghc=ghc-8 but with the
>>> build-system arguments?  Perhaps doing the work in between the Bag and
>>> the Derivation?

Thanks Eric for your suggestion. I made a start on this...

>> You may take a look at the 'package-with-python2' procedure in
>> guix/build-system/python.scm, which seems like it could be adapted to
>> work with haskell/ghc packages.
>
> Hi Eric, Myles,
>
> it seems that the only Python specific part of
> 'package-with-explicit-python' is the keyword '#:python'. What do you
> think of generalizing it by making it a function keyword argument and
> move the procedure to its own module (maybe (guix build-system
> utils)?).

...I came the same conclusion as Fede: it could be generalised.  It is
probably close to working for me (with respect to ghc) so I will keep
going for now.  I am not competent enough to generalise it but if
someone else does I can help test it.

Myles