Extending the dependency syntax

[Ian Lynagh]

On Thu, Jul 28, 2005 at 02:23:55PM -0700, Isaac Jones wrote:
> "Simon Marlow" <simonmar at microsoft.com> writes:
> 
> > So here's a strawman proposal to address some of the use cases raised
> > recently[1] that Cabal doesn't currently support well.  This is just a
> > first attempt; I expect we'll need to make changes or start over if we
> > discover cases that it doesn't handle.
> 
> (snip proposal)
> 
> Lots of this is stuff I've been wanting to ad at some point.  I think
> that rather than overloading the build-depends field, we should add a
> new field for tool dependencies; otherwise, we could get name
> conflicts between the two and such.

Agreed; currently we know that everything in build-depends is a cabal
package we need to depend on, which makes things simpler.

> > build-depends: 
> >   base>=1.0 
> >   (ghc>=6.4 || ghc>=6.2 [ghc62] || hugs-any [hugs]) 

For libraries we(Debian)'d need to be guaranteed that the left-most of
the satisfactory options had been chosen. Otherwise, having built a
library which "build-depends: foo || bar", I don't think we could work
out whether we should depend on libghc6-foo-dev or libghc6-bar-dev (or
equivalent for another impl).


Thanks
Ian