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

Given the objections raised and low cost of defining an alias to (=<<), I withdraw my +1 in favor of a -1. There's a pedagogic cost to bad intuitions from names like flatMap. On Wed, Dec 10, 2014 at 10:43 AM, Andreas Abel wrote:

On 10.12.2014 17:33, John Lato wrote:

...

I don't really understand why people want this. What's wrong with (=<<) ? I kind of feel like a named function should be no longer than that.

You are right, we do not need a alphabetic version of every operator. We do not have

plus = (+)

either. Why take another good name from the user, just to avoid using an operator in parentheses?

I am -1 on the whole business here.

Cheers, Andreas

...

I don't object, especially if others think it's useful (and many clearly do), but I guess it's not to my taste.

On 08:02, Wed, Dec 10, 2014 David Feuer mailto:david.feuer@gmail.com> wrote:

joinMap looks to me like the best name, because it does just what it says on the box:

join . fmap f $ m = (m >>= return . f) >>= id --Functor/Monad law = m >>= (\x -> return (f x) >>= id) --associativity = m >>= (\x -> f x) --left identity = m >>= f --eta reduction = f =<< m

Christopher Done mailto:chrisdone@gmail.com>

writes:

> 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 = (=<<)

I'm -1 on the *name* `bind`, because as others have mentioned, I feel bind has the same type as (>>=).

That said, I'm +1 on the *idea* - if we can find a better name. `joinMap` doesn't seem too bad, as was recently suggested, but I'll settle on anything other than `bind`

-- ocharles

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-- Andreas Abel <>< Du bist der geliebte Mensch.

Department of Computer Science and Engineering Chalmers and Gothenburg University, Sweden

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