• Robert Fraser <fraserofthenight gmail.com> Sep 17 2007

Robert Fraser <fraserofthenight gmail.com> writes:

davidl Wrote:

 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


Isn't this what a static assert is? If you want sets of static assertions, you
can always use template mixins.

template LionAssertions()
{
    static assert(Lion.foodChainPosition == FoodChain.max);
    static assert(Mufasa > Aslan, "this program contains evil lies");
}

class Lion : AwesomenessIncarnate
{
    mixin LionAssertions!()
}