Suggestion for resolving the Cabal/GHC dependency problems

[Duncan Coutts]

On Wed, 2013-09-11 at 17:28 +0100, Duncan Coutts wrote:

> Further, if only ghc-pkg and the ghc build system depend on Cabal, then
> it is easier for Cabal to add more dependencies, since they do not have
> to be installed with ghc (due to the ghc lib depending on them). In
> particular the Cabal folks would like to use a proper parser and have
> suggested adding dependencies on parsec, mtl and transformers. If only
> ghc-pkg depends on Cabal, then these dependencies only need to be used
> at build time, and do not have to be installed (which also means they
> don't have to be kept quite so up to date).

Actually, this is not quite right. Since ghc would still ship Cabal (but
not depend on it), it would also ship its dependencies including parsec,
mtl and transformers. So they would need to be up to date and installed,
it's just that ghc itself would not depend on them.

If that's really inconvenient, it's plausible to have a minimal set
which is just the things ghc depends on, so long as what gets shipped to
users is the useful set, including Cabal.

Duncan