Re: Pointed [Re: 2014 Applicative => Monad proposal]

24 May 2013

      Where is Pointed supposed to live in the hierarchy? For instance, someone
mentioned Set. But Set is not eligible to have a Functor instance.

So do we just have Pointed type functions that aren't necessarily Functors?
And if they are Functors/Applicatives/Monads they're supposed to behave
nicely?

And if not, then several collections are excluded from being Pointed, and
I'm not entirely sure which collections you're using. Just many different
sequence types?

On Fri, May 24, 2013 at 1:02 PM, Andreas Abel wrote:
...
I do not use Pointed a lot, but a situation where it comes natural is when
I want to emit elements into a collection f.  Then I need
Pointed f    -- to emit a single element
  Monoid (f a) -- to join two collections
Using Applicative or Monad is overdoing it.
Maybe you have a better suggestion how to organize my task which I have
not considered yet...
Cheers, Andreas
On 24.05.2013 17:28, Roman Cheplyaka wrote:
...
I completely agree with Edward here.
* Edward Kmett  [2013-05-24 11:20:51-0400]
...
For the record I'm actually -1 on including Pointed.
My experience is that there are very few uses for the class that permit
you
to reason about your code without one-off ad hoc reasoning based on the
particular instance you are given. Now, the Apply and Bind classes on the
other hand... =) Though, to be fair, I couldn't seriously propose
including
either of those, either. Even I can't be bothered to instantiate them all
the time!
-Edward
On Fri, May 24, 2013 at 11:13 AM, Andreas Abel 
**wrote:
+1 AMP
...
+1 MINIMAL
+1 Pointed in base
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Re: Pointed [Re: 2014 Applicative => Monad proposal]

Dan Doel