On Mon, 19 Apr 2010 15:16:46 -0400, Steven Schveighoffer
<schvei...@yahoo.com> wrote:
On Mon, 19 Apr 2010 14:16:03 -0400, Ellery Newcomer
<ellery-newco...@utulsa.edu> wrote:
Hello.
Say I have a [struct] template T, which takes a param S.
Any T!(S) satisfies a certain template constraint W, so I can use any
T!(S) the same way. I want to be able to store heterogeneous T!(S) in a
single list. Is there any good way to express the type for this?
What you are looking for is a conversion from compile-time interface to
runtime interface. The only drawback is, you can't go backwards (from a
runtime interface to a compile-time).
This can be possible in runtime reflection systems, but the theory is
that RTTI can be built from compile-time type info.
Here is a quick-and-dirty solution, if you don't mind using
classes/interfaces. You are going to need some sort of runtime
interface in order to get this to work, classes/interfaces are not the
leanest way to do this, but it should get the job done:
The S is an extra complication that can be factored out, so let's forget
about S for now. Let's assume W defines a single function int
foo(int). Let's make a W interface:
interface IW
{
int foo(int);
}
Now, we can define a class template to hold your values:
class WByVal(T) if (implementsW!T)
Whoops! Forgot the interface!
class WByVal(T) : IW if (implementsW!T)
-Steve
