Proposal: Static Invariant (C++ concept in D)

[davidl]

I've read a little bit stuff of C++ concept, and find it has some  
similarity with
D's runtime invariant in some abstraction. In some extent , we can imagine  
C++
concept is kind of compile time invariant.

So the following:

class TemplateClass(T)
{
   static invariant()   // reuse keywords, nothing more get introduced
   {
     // prerequisite checking, does T have foo , does T have bar
     Base_Concept_check();  // these emulate the inheritance of concept
     Derived_Concept_check();
   }
}

Thanks for the great discussion & help from h3r3tic, LeoD, Alexander,  
Larsivi
They gave me some comments, and ideas.

Though it might not functionate all possiblities of C++ concept , but it  
brings
us a little bit more powerful way to make sure our templates go all fine.  
Hope
people love this idea :D


DavidL