Re: [PATCH] build-system: Add haskell-build-system.

[Ludovic Courtès]

Federico Beffa <address@hidden> skribis:

> Having never used nixpkgs, I'm not sure how they handle the database
> in profiles. Would you have a pointer to a "standard" mechanism (like
> how they handle 'dir' files, icon caches, ...).

AFAIK there’s no general mechanism for that.  For GHC, this is handled
by adding a wrapper for the ‘ghc’ binary:

  
https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/compilers/ghc/wrapper.nix
  
https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/compilers/ghcjs/wrapper.nix

Handling it during profile creation, as you suggest, and avoiding the
use of a wrapper sounds preferable to me.

If you look under
<https://github.com/NixOS/nixpkgs/tree/master/pkgs/desktops/gnome-3/3.12/core>,
many packages have an additional phase that does:

  rm $out/share/icons/hicolor/icon-theme.cache

Some also explicitly wrap executables to set XDG_DATA_DIRS etc. like our
‘glib-or-gtk-build-system’ does:

  wrapProgram $f \
    --prefix XDG_DATA_DIRS : "$XDG_ICON_DIRS:$GSETTINGS_SCHEMAS_PATH"

Thanks,
Ludo’.