[Haskell-cafe] MonadList?

Bertram Felgenhauer bertram.felgenhauer at googlemail.com
Wed Sep 13 17:51:39 EDT 2006

Michael Shulman wrote:
> class MonadList m where
>    option :: [a] -> m a

There's no need for an extra class, it can be done with MonadPlus:

option :: MonadPlus m => [a] -> m a
option = msum . map return

This definition came up before, for example here:



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