Yep. I was backstabbed by ghci seemingly having no issue with my definition when I asked for the type.
On Tue, Apr 16, 2013 at 9:49 PM, Tom Ellis < tom-lists-haskell-cafe-2...@jaguarpaw.co.uk> wrote: > On Tue, Apr 16, 2013 at 01:53:19PM +0100, Oliver Charles wrote: > > On 04/16/2013 01:47 PM, Lyndon Maydwell wrote: > > >You could do: > > > > > >runKleisli . mconcat . map Kleisli :: Monoid (Kleisli m a b) => [a > > >-> m b] -> a -> m b > > > > > >Would that work for you? > > I can't find an instance for Monoid (Kleisli m a b) in `base`, so > > presumably the author would also have to write this instance? If so > > - would that really be any different to using that fold? > > It doesn't make sense anyway. It would have to be "Kleisli m a a" which > would presumably require a newtype. > > Tom > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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