Re: Haskell, anyone?

[mockturtle <framefritti@gmail.com>]

On Monday, November 16, 2015 at 9:33:57 AM UTC+1, Dmitry A. Kazakov wrote:
> On Sun, 15 Nov 2015 14:11:07 -0800 (PST), mockturtle wrote:
> 
> >    function add(X, Y: Integer) return Integer;
> > 
> > rather than
> > 
> >     add :: Integer -> Integer -> Integer
> > 
> > (Yes, I understand that this means that add is a function that maps an
> > integer into a function that maps integers to integers... [confused? :-)]
> 
> Hmm, but that is not an equivalent of "add." In mathematical notation "add"
> is:
> 
>    add : Integer x Integer -> Integer
> 
> a mapping of pairs (Integer, Integer) to Integer.
> 

<disclaimer>
I'm not an expert, I am still at the tutorial level.  What follows is what I understood so far... :-)
</disclaimer>

I agree, but in Haskell tutorials I found the point of view that I described above.  The reason is that in Haskell functions can have only one argument, so if you wants more than argument you need this kind of "iteration."  To be honest, you can also define "add" as a function that maps a pair (x,y) into an Integer, you still have a one-argument function that operates on a single object, that is, a pair.  The iterated function approach allows you to do something like

   inc = add 1

In this case, inc is the Integer -> Integer function returned by "add" called with argument 1.

Source: https://www.haskell.org/tutorial/functions.html