Proposal: Adding Kleisli composition to Control.Monad

[Malcolm Wallace]

Henning Thielemann <lemming at henning-thielemann.de> wrote:

> > > > Add Kleisli composition to Control.Monad.
> > > > 
> > > >     (>=>) :: (Monad m) => (a -> m b) -> (b -> m c) -> (a -> m c)
> > > >     (<=<) :: (Monad m) => (b -> m c) -> (a -> m b) -> (a -> m c)
> > > 
> > > Does anyone have an opinion about these guys? :)
> > 
> > No.  :-)  I've never used them, nor wanted to, so I have no opinion.
> > I can see the nice compositional pattern they embody though.
> 
> Strange, the first time, I used them, was processing HTML data parsed
> by HaXML. :-)

Oops, egg-on-face time.  I had forgotten about that.  Yes, the HaXml
combinators use Kleisli composition extensively (although it is called
`o` there.  And I only recognised that ContentFilter is a monad *very*
recently.)

Regards,
    Malcolm