[Haskell-cafe] The (!) operation

[Francesco Mazzoli]

> Because Maybe is already a monad and it's nice to fail in the monad of
> choice, e.g. if I'm in the list monad I get empty list instead, or if
> I'm in the Result monad from JSON it'll fail in there. ‘Course "fail"
> is suboptimal and MonadError might be better.

'fail' really shouldn't be in Monad. My brain ignores its existence by 
now :).

> Grazie mille, a dopo… ;-)

A dopo!

Francesco