Super-dee-duper D features

[Kirk McDonald]

Sean Kelly wrote:
> Derek Parnell wrote:
> 
>> On Tue, 13 Feb 2007 17:39:46 +0100, Frits van Bommel wrote:
>>
>>> Andrei Alexandrescu (See Website For Email) wrote:
>>>
>>>> Bill Baxter wrote:
>>>>
>>>>> Yeh, I don't get it either.  How would that help me implement 
>>>>> merge() from merge sort for instance?
>>>>
>>>> Merge bumps the iteration in both collections conditionally. The 
>>>> form above bumps the iteration in the two collections 
>>>> unconditionally, until one is finished; then it continues with the 
>>>> other until that is finished.
>>>
>>> In other words, it doesn't :(.
>>
>>
>> I imaging that the full syntax will also include this form ...
>>
>>   foreach (int x, i ; coll1) (int y, j ; coll2)   {
>>    ... use i and j ...
>>      if (somecondition)
>>         x = ...  // To set the index back or forward to some
>>                  // arbitary point in the array 'coll1'.
>>   }
> 
> 
> This currently works for built-in arrays but not for user-defined types. 
>  Also, I think the fact that it works as all is the result of an 
> implementation detail, not spec-defined behavior.
> 
> 
> Sean

There's no reason a user-defined type couldn't implement this.

-- 
Kirk McDonald
http://kirkmcdonald.blogspot.com
Pyd: Connecting D and Python
http://pyd.dsource.org