Go and generic programming on reddit, also touches on D

[Timon Gehr]

On 09/18/2011 07:16 PM, Peter Alexander wrote:
> On 18/09/11 5:08 PM, Timon Gehr wrote:
>> On 09/18/2011 03:48 AM, Andrei Alexandrescu wrote:
>>> Quite interesting.
>>>
>>> http://www.reddit.com/r/programming/comments/kikut/think_in_go_gos_alternative_to_the/
>>>
>>>
>>>
>>>
>>
>> 2 hours ago, Andrei Alexandrescu wrote:
>> > The problem is, Vector was just an example of a multitude of
>> containers. The huge problem with slices is dogfood-related - they are >
>> "magic" because the language features proposed to programmers were not
>> enough for expressing a simple abstraction. Reserving "special" features
>> for the language is a terrible way to go about programming language
>> design.
>>
>> Don't D arrays do a similar thing? They are not templates, yet work with
>> generic element types.
>
> Yes. As I understand, Andrei prefers things in libraries and Walter
> prefers things built in to the compiler (obviously an
> oversimplification, but I believe that's the general way they 'lean').
>
> There's advantages to both. Being implementable in a library means that
> they can easily be swapped out or modified to work with other code, but
> being built-in ("magic", as Andrei puts it) means that the compiler has
> greater awareness of them and can do better optimizations, give better
> errors etc.
>
> Of course, there are ways of extending the language to provide better
> errors and allow better optimizations (e.g. 'pure' in D), but as a
> purely practical matter, it's easier if they are just built-in.
>

Well, I think arrays should be built-in. What I was implying was that D, 
not entirely unlike Go, also has some magic. You can get almost the same 
with templates, so it is way better in that aspect than Go, but it is 
still there.

>
>> Afaics, improving the language to the point were dynamic array-like
>> structures could be implemented in the library without resulting in a
>> bloated executable would be quite involved.
>
> I don't think you'd get much bloat in D by implementing dynamic arrays
> with templates.  Remember, the built-in arrays *are* mostly implemented
> in D: https://github.com/D-Programming-Language/druntime/tree/master/src/rt

Those work like generics, not like templates. Making them templates 
would duplicate all the runtime functions that process arrays for every 
element type it is instantiated with. And I am sure that would add some 
bloat. D has no generics, just templates. But built-in arrays work like 
generics.