bind :: Monad m => (a -> m b) -> m a -> m b

Joseph Abrahamson me at
Tue Dec 9 22:01:04 UTC 2014

I’m +1 on this. Not only is it nice to sometimes have a non-operator (>>=) but it’s nice to have a function which more obviously lifts Kleisli arrows to monad arrows. Since it’s all aesthetics here, I think `bind f` is nice.

Bob, ap is useful with the Monad constraint because it lets you define (<*>) just using an already written Monad instance. It looks like it’s staying that way too

On Tue, Dec 9, 2014 at 4:55 PM, Bob Ippolito <bob at> wrote:

> +1 from me, I would love to have named versions of these operators.
> Does `ap` still have a Monad constraint or has it been changed to match the
> Applicative `<*>` after AMP?
> On Tue, Dec 9, 2014 at 1:44 PM, Christopher Done <chrisdone at>
> wrote:
>> Is this defined anywhere in base, and if not could it be placed in
>> Control.Monad? I often find myself writing:
>> fmap (mu bar)
>>      (foo zot)
>> Then I decide to change the type of x, so instead I want to just
>> write:
>> bind (mu bar)
>>      (foo zot)
>> Which is just like fmap but the function can run in the
>> monad. Similar to traverse:
>> (Traversable t, Applicative f) => (a -> f b) -> t a -> f (t b)
>> As someone who isn’t a fan of operators, I generally am appreciative
>> of alternative regular plain English word versions of functions, which
>> I find easier to type, read and edit. Currently without defining such
>> a handy name, I have to transform the code to this:
>> mu bar =<<foo zot
>> The name for this function is a no-brainer:
>> bind :: Monad m => (a -> m b) -> m a -> m bbind = (=<<)
>> For comparison, the not-very-pleasant <$> and <*> each have word
>> alternatives, fmap and ap. Even <> has mappend.
>> I don’t hold much hope for this, Haskellers love operators as much as
>> Perl programmers so few on this list will see the value in plain old
>> words, but at least I can link to this email in the archives for
>> future reference.
>> Ciao
>> _______________________________________________
>> Libraries mailing list
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