• llee (6/6) Aug 09 2008 I'm working on a set library that uses templates. The library centers ar...
• Koroskin Denis (19/30) Aug 09 2008 t =

llee <llee goucher.edu> writes:

I'm working on a set library that uses templates. The library centers around a
class named Set. This class contains an array named elems that stores the set's
elements. The definition for set is as follows:

     class Set (T) { ... T[] elems; ... }

To calculate the cartesian product of two sets, I need to be able to represent
higher order sets. I tried defining a function with the following signiture:

     static Set! (Set! (T)) product (Set! (T) a, Set! (T) b);

Unfortunately, the dmd compiler throws an error stating that It does no allow
recursive elements.

Does anyone know how to work around this problem?

"Koroskin Denis" <2korden gmail.com> writes:

On Sat, 09 Aug 2008 21:40:24 +0400, llee <llee goucher.edu> wrote:

 I'm working on a set library that uses templates. The library centers =

 =

 around a class named Set. This class contains an array named elems tha=

t  =

 stores the set's elements. The definition for set is as follows:

      class Set (T) { ... T[] elems; ... }

 To calculate the cartesian product of two sets, I need to be able to  =

 represent higher order sets. I tried defining a function with the  =

 following signiture:

      static Set! (Set! (T)) product (Set! (T) a, Set! (T) b);

 Unfortunately, the dmd compiler throws an error stating that It does n=

o  =

 allow recursive elements.

 Does anyone know how to work around this problem?

Can't confirm. The following code works:

class Set (T) {
	T[] elems;
}

Set!(Set!(T)) product(T)(Set!(T) a, Set!(T) b)
{
	Set!(Set!(T)) r =3D null;
	// do something
	return r;
}

void main()
{
	auto t =3D new Set!(int);
	auto s =3D product(t, t);
}