Re: [PATCH 0/2] native-search-paths for GHC

[Eric Bavier <ericbavier@openmailbox.org>]

Hello Guix,

With all the Haskell packages that have made their way to the list, I 
was wondering if anyone had any further comments on these patches.

`~Eric

On 2015-10-06 16:26, ericbavier@openmailbox.org wrote:
> From: Eric Bavier <bavier@member.fsf.org>
> 
> The first of these patches lets search-path-as-list function correctly 
> when a
> pattern is given and the 'directory file type is specified.
> 
> The second adds a native-search-paths field to our ghc package.  It 
> modifies
> our haskell-build-system to install a package-specific package database 
> with
> each haskell library.  GHC insists on a binary package cache file 
> called
> 'package.cache' to be in each directory listed in GHC_PACKAGE PATH, so 
> we
> uniquely name the package database directories, and use a file-pattern 
> to add
> those to GHC_PACKAGE_PATH.
> 
> The benefit of this over the current situation is that one gets the 
> benefit of
> `guix package --search-paths`.  Currently, after installing ghc 
> packages, the
> user needs to know to manually add
> ~/.guix-profile/lib/ghc-7.8.4/package.conf.d to their GHC_PACKAGE_PATH. 
>  GHC
> package recipes would no longer need to propagate runtime dependencies, 
> and
> 'guix environment' also works nicely out-of-the-box::
> 
> $ guix environment --ad-hoc ghc ghc-attoparsec
> $ ghc-pkg list
> /gnu/store/...-ghc-mtl-2.1.3.1/lib/ghc-7.8.4/ghc-mtl-2.1.3.1.conf.d
>    base-4.7.0.2
>    ghc-prim-0.3.1.0
>    integer-gmp-0.5.1.0
>    mtl-2.1.3.1
>    rts-1.0
>    transformers-0.3.0.0
> /gnu/store/...-ghc-regex-base-0.93.2/lib/ghc-7.8.4/ghc-regex-base-0.93.2.conf.d
>    array-0.5.0.0
>    base-4.7.0.2
>    bytestring-0.10.4.0
> ...
> /gnu/store/4vvmngz1w8ccm7v7mk4f4dxk45834464-ghc-attoparsec-0.13.0.0/lib/ghc-7.8.4/ghc-attoparsec-0.13.0.0.conf.d
>    array-0.5.0.0
>    attoparsec-0.13.0.0
> ...
> 
> Though, as you can see in this example, libraries may be listed more 
> than
> once.  As far as I can tell at this point, that is just an aesthetic 
> detail.
> 
> Future work might involve filtering build-only library dependencies 
> from the
> generated package database.  We could probably also remove the ghc 
> package
> database creation during profile generation.
> 
> I'd be insterested in hearing others' thoughts on this approach.
> 
> Eric Bavier (2):
>   utils: Have search-path-as-list pattern search for directories.
>   gnu: ghc: Add GHC_PACKAGE_PATH native search path.
> 
>  gnu/packages/haskell.scm            |   6 +++
>  guix/build/haskell-build-system.scm | 100 
> +++++++++++++++++++++++++++++-------
>  guix/build/utils.scm                |   9 ++--
>  guix/search-paths.scm               |   6 ---
>  4 files changed, 93 insertions(+), 28 deletions(-)

-- 
`~Eric