proposal for ghc-pkg to use a directory of .conf files

[Simon Marlow]

On 06 November 2004 10:10, Sven Panne wrote:

> Duncan Coutts wrote:
>> I can knock up a proof of concept patch if anyone thinks this is a
>> good idea. It should be totally backward compatible, it's ok to use
>> both, but ditro packagers might like to enforce a policy of using a
>> directory of package files for external libraries.
> 
> OK, just send us a patch and if there are no objections we can merge
> it into the HEAD.

In some ways this looks like a good idea, but it contradicts some of the
ideas in the Cabal proposal.  There, we were treating the package
database as an abstract entity hidden behind the ghc-pkg interface.  All
interaction with the database would be done via ghc-pkg.

The advantages of this abstraction are the usual ones: we might want to
change the representation, and the ghc-pkg tool provides a good place to
add backwards compatibility if necessary.

However, I'm prepared to be persuaded.  The "just put a file in this
directory" approach to installation is very compelling, being much more
transparent.  But bear in mind that if we pick this route, then
backwards compatibility has to be built into the file format (I think it
might be already, but we're planning changes in this area to better
support Cabal).  

Also, there needs to be a way to find the location to install the file -
asking ghc or ghc-pkg is the usual way.

Cheers,
	Simon