Non-H98 crusade, contd.

[John Meacham]

On Mon, Feb 28, 2005 at 06:47:05PM +0000, Malcolm Wallace wrote:
> Andrew Pimlott <andrew at pimlott.net> writes:
> 
> > On Mon, Feb 28, 2005 at 01:45:25PM +0000, Malcolm Wallace wrote:
> > > As examples of language features that should be removed or revised,
> > > how about these:
> > 
> > Perhaps
> > 
> >     (d) the restriction of list comprehension to lists (instead of
> >         MonadPlus)
> 
> You do realise that we used to have monad comprehensions in Haskell
> 1.4, and they were deliberately removed for Haskell'98?  The reason
> was that error messages for beginners' code were rather baffling.
> (And pretty baffling for some experts too!)  In any case, the
> do notation is exactly analogous to list comprehensions with the
> restriction to a single monad lifted.

Does the incredibly useful parallel list comprehension extension in ghc
generalize to arbitrary monads? or MonadPluses even? 
        John

-- 
John Meacham - ⑆repetae.net⑆john⑈