What's wrong with D's templates?

[Lutger]

Yigal Chripun wrote:

> On 18/12/2009 02:49, Tim Matthews wrote:
>> In a reddit reply: "The concept of templates in D is exactly the same as
>> in C++. There are minor technical differences, syntactic differences,
>> but it is essentially the same thing. I think that's understandable
>> since Digital Mars had a C++ compiler."
>>
>> 
http://www.reddit.com/r/programming/comments/af511/ada_programming_generics/c0hcb04?context=3
>>
>>
>> I have never touched ada but I doubt it is really has that much that
>> can't be done in D. I thought most (if not all) the problems with C++
>> were absent in D as this summary of the most common ones points out
>> http://www.digitalmars.com/d/2.0/templates-revisited.html.
>>
>> Your thoughts?
> 
> I don't know Ada but I do agree with that reddit reply about c++ and D
> templates. D provides a better implementation of the exact same design,
> so it does fix many minor issues (implementation bugs). An example of
> this is the foo<bar<Class>> construct that doesn't work because of the
> ">>" operator.
> However, using the same design obviously doesn't solve any of the deeper
> design problems and this design has many of those. An example of that is
> that templates are compiled as part of the client code. This forces a
> library writer to provide the source code (which might not be acceptable
> in commercial circumstances) but even more frustrating is the fact that
> template compilation bugs will also happen at the client.

Well yes, but the .NET design restrict the generic type to a specific named 
interface in order to do type checking. You may find this a good design 
choice, but others find it far more frustrating because this is exactly what 
allows for a bit more flexibility in a statically typed world. So it is not 
exactly a problem but rather a trade-off imho.