On Wed, 5 Sep 2007, ok wrote:
On 5 Sep 2007, at 6:16 pm, Henning Thielemann wrote:
I think it is very sensible to define the generalized function in terms of
the specific one, not vice versa.
The specific point at issue is that I would rather use ++ than
`mplus`. In every case where both are defined, they agree, so
it is rather frustrating to be blocked from using an operator
which would otherwise have been appropriate.
What is your application, where you need (++) frequently? Today I like
that (++) points me to the fact, that we are working on lists. Ok, I would
be fine, if (++) would be a method for all sequence types. But for
MonadPlus, this is too general for my taste.
I am a little puzzled that there seems to be no connection between
MonadPlus and Monoid. Monoid requires a unit and an associative
binary operator. So does MonadPlus. Unfortunately, they have different
names. If only we'd had (Monoid m, Monad m) => MonadPlus m...
Monoid is of kind *
MonadPlus is of kind * -> *
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