benefits of extralibs/consequences of exceptions (Re: head aches in parser/Parser.hs)

[Simon Marlow]

Claus Reinke wrote:

> Btw, are the exception changes meant to lead to another round
> of library breakage/updates, or is this just the compatibility mode
> not yet being in place?

We're planning to have some backwards compatibility in place for the 6.10.1 
release (maybe I'd get a chance to work on it if you folks would stop 
sending emails I need to reply to :-p).

What we plan to do is provide a package called base-3.x in addition to 
base-4.x.  base-3.x will depend on base-4.x, but have the same API as the 
existing base-3.x in GHC 6.8.

Packages that explicitly depend on base-3.x will continue to work. 
Unfortunately these are few and far between, despite our warnings after the 
6.8 release.  So in order to keep most packages working we intend to try 
building the whole of Hackage, identify those packages that have been 
broken by API changes, and fix their .cabal files in the Hackage database. 
  This will mean that packages installed by cabal-install will work, but if 
you download the tarball and try to build with Cabal it might still fail. 
I think that's the best we can do for now, though.

Cheers,
	Simon