Duplicating multidimensional array

[Ali Çehreli]

On 05/30/2013 04:48 PM, Ali Çehreli wrote:

 > For classes, there is no syntax for copying. The type may have annotated
 > a member function that it is the duplication function or we may know by
 > convention that dup() is the equivalent of array .dup.

Kenji Hara responded to another thread on the main D newsgroup. 
Apparently, such a convention-based functionality is already being used 
by std.conv.to. Here is the excerpt:

On 05/30/2013 07:13 PM, Kenji Hara wrote:

 > Current D does not provide generic way for deep copy of class object.
 > But, you can use std.conv.to with adding a kind of copy constructor.
 >
 > class C
 > {
 >      int x;
 >      this(int n) { x = n; }
 >
 >      // Do deep copy, this is used by to!(array-type)(array)
 >      this(const C c) { this.x = c.x; }
 > }
 > void main()
 > {
 >      const(C)[] carr = [new C(1), new C(2)];
 >      // C[] marr = carr.dup;
 >      // --> Error: cannot implicitly convert element type const(C) to
 > mutable in carr.dup
 >
 >      import std.conv;
 >      C[] marr = carr.to!(C[]);
 >      // For class arrays which need copy elements,
 >      // std.conv.to returns [new C(carr[0]), new C(carr[1]), ...]
 >
 >      // modify element of returned array
 >      marr[0].x = 5;
 >
 >      // Right now carr[0] and marr[0] are completely unrelated objects
 >      assert(carr[0].x == 1);
 >      assert(marr[0].x == 5);
 > }
 >
 > Kenji Hara

Ali