patch applied (packages/containers): Remove the rest of base to leave a "containers" package

[Isaac Dupree]

Bulat Ziganshin wrote:
> "lower down" - ok, but not in base if possible. base can't be upgraded
> without upgrading ghc and anything contained here is almost dead for
> timely improvements
> 

Is it time to take Prelude and many classes out of base so they can be 
upgraded too, maybe a 'prelude', maybe a 'base-classes' package?  Of 
course naming will be difficult and once base has shrunk enough, maybe 
it should be called something other than "base" then, although that's 
not necessary.  Arguing for Prelude is if something in the library needs 
to be fixed up for Haskell-prime compliance sometime (the only change 
that seems likely to happen to Prelude!).  On the other hand many of the 
standard classes and instances are currently defined in a way that is 
tangled amongst the un-upgradable code, so problems with those standard 
instances (like <http://hackage.haskell.org/trac/ghc/ticket/1579> maybe) 
might not actually be fixable anyway without more-extensive refactoring 
work.  Also arguing against taking Prelude out of base is if base is 
supposed to support some compilers that can't handle Prelude not being 
available!

Packages consisting of only classes are mostly good, but they require 
the types they refer to and default implementations.  Not much of a 
problem - class-default implementations probably shouldn't be too 
complicated.

Isaac