April 19, 2007
Here's a simplified version of the code I'm trying to get working. Honestly, I didn't expect it to work, but I was hoping...

Is there any hope for this style of usage to work?  I'm pleasantly surprised by it compiling at all.  In the full implementation, the templated calls to X occur after a few more layers of obfuscation.  If the below code really does compile and link correctly, I can give a more complex example.

Essentially, I only expect the compiler to be able to figure out how the interface is used, but it has to also force the classes extending from it to define the extra versions of foo.

File 1:
interface X{
  void foo(A)();
}

class Y: X{
  void foo(A)(){};
}

class Z: X{
  void foo{A)(){};

// etc...

File 2:
int main(char [] args){
  X y = new Y();
  X z = new Z();
  y.foo!(int)();
  z.foo!(char)();
}
April 19, 2007
"Jason House" <jason.james.house@gmail.com> wrote in message news:f06cse$h1b$1@digitalmars.com...
> Here's a simplified version of the code I'm trying to get working. Honestly, I didn't expect it to work, but I was hoping...
>
> Is there any hope for this style of usage to work?  I'm pleasantly surprised by it compiling at all.  In the full implementation, the templated calls to X occur after a few more layers of obfuscation.  If the below code really does compile and link correctly, I can give a more complex example.

It might compile, but it might not do what you expect it to.  Templated member functions (and interface methods) are never virtual and therefore cannot participate in polymorphism.  :\


April 19, 2007
Jarrett Billingsley wrote:
> "Jason House" <jason.james.house@gmail.com> wrote in message news:f06cse$h1b$1@digitalmars.com...
>> Here's a simplified version of the code I'm trying to get working. Honestly, I didn't expect it to work, but I was hoping...
>>
>> Is there any hope for this style of usage to work?  I'm pleasantly surprised by it compiling at all.  In the full implementation, the templated calls to X occur after a few more layers of obfuscation.  If the below code really does compile and link correctly, I can give a more complex example.
> 
> It might compile, but it might not do what you expect it to.  Templated member functions (and interface methods) are never virtual and therefore cannot participate in polymorphism.  :\ 
> 
> 

That seems to imply that having a variable of interface type should not be allowed if that interface contains templated member functions...
April 19, 2007
"Jason House" <jason.james.house@gmail.com> wrote in message news:f06gv1$mcd$1@digitalmars.com...
>
> That seems to imply that having a variable of interface type should not be allowed if that interface contains templated member functions...

Or make templated member functions in interfaces illegal, since they can't ever be overloaded, and what's an interface for, after all?


April 20, 2007
Jarrett Billingsley wrote:
> "Jason House" <jason.james.house@gmail.com> wrote in message news:f06gv1$mcd$1@digitalmars.com...
>> That seems to imply that having a variable of interface type should not be allowed if that interface contains templated member functions...
> 
> Or make templated member functions in interfaces illegal, since they can't ever be overloaded, and what's an interface for, after all? 
> 
> 

I was thinking about that.  An interface can be used to define what a class should contain even if it can't be used in any polymorphic sense. 
 I can then make a function templated to accept a class and assume it conforms to an interface (maybe a static check?).  Sadly, when I did that, the call to the templated member function failed to get linked in. 
 Commenting out the interface use fixed the problem.  Weird...
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