Super-dee-duper D features

[Sean Kelly]

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