Re: [PATCH] profiles: Generate GHC's package database cache.

[Federico Beffa <beffa@ieee.org>]

On Sun, Apr 5, 2015 at 7:21 AM, Mark H Weaver <mhw@netris.org> wrote:
> I believe this will require GHC to build *any* non-empty profile.  Since
> GHC is only available on Intel platforms, this will break profile
> building on MIPS and ARM.
>
> Even on Intel platforms, I don't want to have to install GHC to build
> profiles that don't contain any Haskell packages, especially since it
> involves trusting the upstream binaries from GHC.

Good point. Would this check be satisfactory for you?

  ;; Don't depend on GHC when there's nothing to do.
  (if (any (cut string-prefix? "ghc" <>)
           (map manifest-entry-name (manifest-entries manifest)))
      (gexp->derivation "ghc-package-cache" build
                        #:modules '((guix build utils))
                        #:local-build? #t)
      (gexp->derivation "ghc-package-cache" #~(mkdir #$output))))

>
> What if I want to use Hugs instead, or some other Haskell implementation
> that is capable of being bootstrapped from source code.  Is GHC the only
> tool that can do this job?

As far as I know, the library database is compiler specific. Here we
are handling GHC only. But, if you know better, don't hesitate to make
a concrete suggestion.

Regards,
Fede