It might be useful to relax the type of the function to
Monad m => (a -> b -> c) -> m a -> m b -> m c

/Jonas

On 30 May 2010 10:35, Michael Vanier <[email protected]> wrote:
> I stumbled across this monadic combinator:
>
> mcombine :: Monad m => (a -> a -> a) -> m a -> m a -> m a
> mcombine f mx my = do
>    x <- mx
>    y <- my
>    return (f x y)
>
> I used it to chain the outputs of two Parsec String parsers together using
> this operator:
>
> (<++>) :: Monad m => m String -> m String -> m String
> (<++>) = mcombine (++)
>
> mcombine seems like such a basic operation that it should be a library
> function, but I couldn't find one matching it on hoogle.  Is there one?
>
> - Mike
>
>
>
>
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