Super-dee-duper D features

[renoX]

Andrei Alexandrescu (See Website For Email) a écrit :
> renoX wrote:
>> Andrei Alexandrescu (See Website For Email) a écrit :
>>> 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.

I wouldn't call 'functional flavored' something with such an 'hidden 
state' stored in i, but that's just me.
And I have a question for the safety: what is supposed to happen if the 
programmer modifies coll1 between the foreach(i ; coll1) and continue 
foreach?
Adding or removing value in the collection before the continue foreach?

Just being curious, I would imagine that this is just forbidden.

renoX

> 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