Hello
I want to write "map" function with the Common Lisp "mapcar" behaviour. But i don't understand how to write one template for the N-argument delegate.
This is how it works now:

T[] map(T, T1)(T delegate(T1) fun, T1[] xs) {
  T[] result; result.length = xs.length;
  foreach (i,x; xs)
    {
      result[i] = fun(x);
    }
  return result;
}
T[] map(T,T1,T2)(T delegate(T1, T2) fun, T1[] xs, T2[] ys) {
  T[] result; result.length = reduce!(min)(xs.length,[ys.length]);
  for (int i = 0; i<result.length; ++i)
    {
      result[i] = fun(xs[i], ys[i]);
    }
  return result;
}

How can i improve the code?

Thank you

On Sun, 06 Jul 2008 02:19:09 +0400, baleog <maccarka@yahoo.com> wrote:

> Hello
> I want to write "map" function with the Common Lisp "mapcar" behaviour. But i don't understand how to write one template for the N-argument delegate.
> This is how it works now:
>
> T[] map(T, T1)(T delegate(T1) fun, T1[] xs) {
>   T[] result; result.length = xs.length;
>   foreach (i,x; xs)
>     {
>       result[i] = fun(x);
>     }
>   return result;
> }
> T[] map(T,T1,T2)(T delegate(T1, T2) fun, T1[] xs, T2[] ys) {
>   T[] result; result.length = reduce!(min)(xs.length,[ys.length]);
>   for (int i = 0; i<result.length; ++i)
>     {
>       result[i] = fun(xs[i], ys[i]);
>     }
>   return result;
> }
>
> How can i improve the code?
>
> Thank you

There already exists a map function in D2, see std.algorithm (http://www.digitalmars.com/d/2.0/phobos/std_algorithm.html), take a loop at it.