Functor, Applicative, Monad, Foldable, Traversable instances for (, , ) a b

[Henrik Nilsson]

On 04/06/2017 04:15 AM, Tony Morris wrote:
> By "length" here I mean, the function whose name is lima echo november
> golf tango hotel. I truly do not care what it is called. Follow the
> types, and the types of the types.

I think the nub of the matter is that the types (and the types of the 
types) (in a language like Haskell) actually are not enough. There are
(literally) infinitely many functions with the same type as "length".
One might argue that few of those make "sense", but that is always
going to be a precarious argument unless the setting is made clear.

More generally, if we were to extrapolate and truly refer to things
by their full specification, then that would be very cumbersome indeed.
By analogy, mathematical theorems are full specifications, and they
usually have names.

Names matter, at least to most people (I dare guess), and in particular
when we rely on the names to convey missing information, as is the
case with "length" given its (Haskell) type.

Best,

/Henrik





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