What features of D are you using now which you thought you'd never goint to use?

[monarch_dodra]

On Monday, 24 June 2013 at 22:27:19 UTC, Brad Anderson wrote:
> On Sunday, 23 June 2013 at 01:34:53 UTC, Andrei Alexandrescu 
> wrote:
>> On 6/22/13 2:58 PM, monarch_dodra wrote:
>>> long story short: we don't have rfind. C++ does.
>>
>> We do, just that it's for random-access ranges. C++ offers it 
>> for bidirectional ranges too. We could of course support it if 
>> bidirectional ranges were required to have something like 
>> r1.before(r2) that, assuming r2 is reachable from r1, returns 
>> the portion in r1 that's before r2.
>>
>> Andrei
>
> How efficiently could before() be implemented?

In terms of efficiency, it would really depend on the range that 
implements it, but I'd say "o(1)": cheap. The problems are (imo):
*defining the exact semantics that go with it.
*defining the traits that go with it.

One big hurdle (I think), is that there is no way to provide a 
default implementation, even for RA ranges with slicing. And 
that's very bad.

I'm going to get bashed for this, but I think the concept of 
"iterable" range would be a much simpler concept: Far be for me 
to want iterators as the norm (puke), but being able to 
temporarily view a range (if possible), as two end points, before 
re-creating the range from said points, has some very simple, and 
easy to understand, yet efficient, semantics.

It's really the only way to provide slicing for ranges that 
aren't RA...

Eg:
Range r;
Range r10 = Range(r.begin, advance(r.begin, 10));