class scope virtual template functions

[janderson]

Chris Wright wrote:
> janderson wrote:
>> Sorry, I haven't actually tried this example.  Its an C++ trick I've 
>> used for other purposes.  I think it looks something like this:
>>
>> class TemplateMaker
>> {
>>    TemplateMakera(delegate) { record of stuff ... } //This might be a 
>> template too, can't remember. Maybe a reinterpret cast somewhere too.
>>    void opCall(T...)(T arg) { delegate->recoredcallback(arg); }
>> }
>>
>> I'm sure given enough time it could be done in D like C++.  I don't 
>> want to put in the effort though atm.
>>
>> -Joel
> 
> Delegates can work. But you have to know the arguments to the template 
> in advance.
> 
> Everything I can think of to implement virtual templates requires 
> virtual templates. With the exception of hacking the compiler, which 
> would provide a means of providing virtual templates. It's a 
> straightforward matter, so it wouldn't require redesign like const, 
> though the initial effort might well be greater.

I agree that having virtual templates in the language would be nice.  I 
don't like using workaround because they are less intuitive.

-Joel