On 2/24/13 1:50 PM, Timon Gehr wrote:
> On 02/24/2013 04:59 AM, Steven Schveighoffer wrote:
>> ...
>>
>> D is much different (and better IMO)
>> ...
>
> IMO The best way to think about it is that the two approaches are not
> comparable. D templates are a kind of hygienic macro system for
> declarations. Java does not have this. Java generics make the type
> system more expressive. D lacks this kind of expressiveness.

I'd think type erasure techniques make it possible to emulate Java's generics in D, whereas D's templates can't be emulated in Java.

Andrei

On 02/24/2013 05:20 PM, Andrei Alexandrescu wrote:
> On 2/24/13 1:50 PM, Timon Gehr wrote:
>> On 02/24/2013 04:59 AM, Steven Schveighoffer wrote:
>>> ...
>>>
>>> D is much different (and better IMO)
>>> ...
>>
>> IMO The best way to think about it is that the two approaches are not
>> comparable. D templates are a kind of hygienic macro system for
>> declarations. Java does not have this. Java generics make the type
>> system more expressive. D lacks this kind of expressiveness.
>
> I'd think type erasure techniques make it possible to emulate Java's
> generics in D,

The compile-time type checking and avoidance of type erasure in user code aspects are the only important features of Java generics. This is most obvious noting that pre-generic Java also supports the techniques you mention.

>  whereas D's templates can't be emulated in Java.
>

If type erasure is considered a means to emulate generics in D, then IMHO copy pasta should also be considered a means to emulate templates in Java. Otherwise the viewpoint could be considered biased. But I think usually they just use external code generation frameworks.