File locations for cabal-install

[Alson Kemp]

> A question for the group:
>    Where should cabal-install's various files go?
> 
> Note:
>   None of the cabal-install files is dependent on a particular
> version
> of Cabal or GHC, so the files do not need to be stored in
> versioned-directories (e.g. Cabal-1.1.5 or Cabal-1.1.5/ghc-6.4.2).
> 
> Files:
>    server.list - one line config file with the Hackage server
> location,
> basically never modified;
>    package.list - the listing of packages available on the Hackage
> server;
>    packages/ - the directory in which all of the downloaded packages
> are stored.
> 
> Options:
>    1) Proper: /etc/server.list,
> /var/local/lib/cabal-install/package.list,
> /var/local/lib/cabal-install/packages/.  A bit dogmatic and I'm not
> sure how it maps onto non-*nix systems, but it's the Right Thing to
> do
> on *nix.
>    2) Easy: everything goes in $lib-prefix/cabal-install.  Isn't the
> prettiest solution, but it's functional.  Maps onto Windows well. 
> Users will never directly see or use these files, so
> $lib-prefix/cabal-install.  (GHC does this with its package.conf.) 
>    3) [other suggestions?]
> 
> 
> I think that Isaac prefers Option 1 because it's the proper way to do
> things; I prefer Option 2 because it's a pretty good solution even if
> it isn't *nixy.
> 
> Opinions? Arguments?  Suggestions?
> 
>   - Alson