Function tuples

[Ali Çehreli]

On 03/14/2014 09:37 AM, bearophile wrote:
> This comes from a Rosettacode entry:
> http://rosettacode.org/wiki/First-class_functions#D
>
>
> import std.stdio, std.math, std.typetuple, std.functional;
>
> enum static sin  = (in real x) pure nothrow => std.math.sin(x),
>              asin = (in real x) pure nothrow => std.math.asin(x),
>              cos  = (in real x) pure nothrow => std.math.cos(x),
>              acos = (in real x) pure nothrow => std.math.acos(x),
>              cube = (in real x) pure nothrow => x ^^ 3,
>              cbrt = (in real x) /*pure*/ nothrow => std.math.cbrt(x);
>
> void main() {
>      alias dir = TypeTuple!(sin,  cos,  cube);
>      alias inv = TypeTuple!(asin, acos, cbrt);
>      foreach (immutable i, f; dir) {
>          writefln("%6.3f %6.3f",
>                   compose!(f, inv[i])(0.5),
>                   compose!(dir[i], inv[i])(0.5));
>      }
> }
>
> It prints:
>
>   0.500  0.500
>   0.866  0.500
>   0.713  0.500

DMD64 D Compiler v2.066-devel-1a70764 prints the following for me:

  0.500  0.500
  0.500  0.500
  0.500  0.500

Maybe a bug fixed? (Or a bug introduced if you are using a more recent 
one. :) )

>
> Do you know why there's such difference in the results?
>
> (You can't define a staticZip in D?)
>
> Bye,
> bearophile

Ali