How to define templates

[Walter Bright]

Steve Teale wrote:
> Also, would it be reasonable for the compiler to issue a warning or
> error message to the effect that T, U, and V were never mentioned in
> the template body.

No, because the template signature may be conforming to an externally 
applied interface, and may simply not need the args.

> What is the basic difference between Templates and Macros - the
> declarations thing is obviously crucial, but why?

Macros manipulate text, templates manipulate syntax trees. They happen 
at very different stages in compilation.