A currying function

[Artur Skawina]

On 06/21/12 21:04, Philippe Sigaud wrote:
> On Tue, Jun 19, 2012 at 2:52 PM, Artur Skawina <art.08.09 at gmail.com> wrote:
> 
>> I'm not really sure when you'd want to use this in D.
> 
> As for Haskell. For example, with a range of ranges and you want to
> take the first 100 elements of all subranges:
> 
> alias Curry!take ctake;
> 
> auto target = [[0,1,2,...], [...], ];
> auto first100s = map!(ctake(100))(target);
> 
> And so on. When mapping and filtering ranges, I need currying from
> time to time.

Sure, but partial application would be enough for cases like this one.

   auto partappe(alias F, A...)(auto ref A a) {
      auto ref f(ParameterTypeTuple!F[0..$-A.length] b) { return F(b, a); }
      return &f;
   }
   
   int n = 2;
   auto target = [[0,1,2], [3,4,5], [6,7,8]];
   auto takeN = partappe!(take!(int[]))(n);
   auto firstN = map!takeN(target);

I wonder if there's a case for "real" currying in 'D'; still can't think
of one, but maybe that's just because it's not how i would usually code it.
   
artur