[jhc] darcs patch: try to abstract IO a bit

[John Meacham]

An issue is that the newtype for IO needs to be in Jhc.Prim, Jhc.Prim is
included as a dependency for every module because it has things that the
compiler needs to exist no matter what you are building. This doesn't
mean that Jhc.IO has to export it non-abstractly, and allowing it to be
fully abstract is useful, but we need to move the actual newtype back
into Jhc.Prim. 

Just because an IO in Jhc.Prim exists, it doesn't mean you can't provide
an alternate IO via a package of course.

You might be interested in Jhc.JumpPoint, which was the original
implementation of IO exceptions. now, we actually have Grin primitives
for continuations, though they arn't currently used, they may be useful
for what you are doing. See 'MkCont' in Grin.Grin.

        John

-- 
John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/