Super-dee-duper D features
janderson
askme at me.com
Tue Feb 13 22:27:55 PST 2007
Andrei Alexandrescu (See Website For Email) wrote:
> renoX wrote:
>> Andrei Alexandrescu (See Website For Email) a écrit :
>>> James Dennett wrote:
>>>> C++, of course, has std::for_each(e.begin(), e.end(), do_x);
>>>> in its library (though that's weaker than it could be because
>>>> of lack of support for convenient anonymous functions/lambdas).
>>>>
>>>> C++0x is very likely to have for(v: e). It's implemented
>>>> in ConceptGCC already. Java already has essentially that,
>>>> as does C#. This really doesn't set D apart (but at least
>>>> D isn't falling behind here).
>>>
>>> BTW, D might soon have simultaneous iteration that will blow away all
>>> conventional languages:
>>>
>>> foreach (i ; coll1) (j ; coll2)
>>> {
>>> ... use i and j ...
>>> }
>>> continue foreach (i)
>>> {
>>> ... coll2 finished; use i ...
>>> }
>>> continue foreach (j)
>>> {
>>> ... coll1 finished; use j ...
>>> }
>>>
>>> Best languages out there are at best ho-hum when it comes about
>>> iterating through simultaneous streams. Most lose their elegant
>>> iteration statement entirely and come with something that looks like
>>> an old hooker early in the morning.
>>
>> At first, I really didn't like the 'continue foreach', then afterwards
>> I got used to it, I wonder if this is really such a requested feature
>> though, what's wrong with the good old 'for' or 'while' for the
>> complex case?
>
> Absolutely nothing's wrong. The same argument, however, could be
> formulated to render foreach redundant. We have for, don't we.
>
> The thing is foreach is terse and elegant and has a functional flavor
> that gives it safety and power that for doesn't have. It's only natural
> to ask oneself why all of these advantages must go away in a blink just
> because you want to iterate two things simultaneously.
>
>
> Andrei
I think its about how much this feature will be used. This one seems
like it could be useful but its pretty close to borderline-"feature for
feature sake" for me. There are probably a lot of other features that
could be more useful then this one.
-Joel
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