[LLVMdev] Removing std::vector from APIs (was Re: Mutating the elements of a ConstantArray)

[Chris Lattner]

On May 15, 2009, at 10:52 AM, Gordon Henriksen wrote:

> On 2009-05-15, at 07:26, David Greene wrote:
>
>> On Friday 15 May 2009 05:50, Jay Foad wrote:
>>>
>>
>>>> The one major thing to be aware of is that it isn't safe to use
>>>> &V[0] when V is an empty std::vector
>>>
>>> Oh dear. That's a bit of a flaw in the plan. I suppose the solution
>>> is to switch to SmallVector whenever this might be a problem.
>>
>> Or use iterators.  That's why they're there.
>
> The reason to use the pointer-length pair in preference to iterators
> is that iterators make templates of everything, causing code bloat. In
> my code, rather than pass the separate parameters I use a range<Iter>
> class something like this:

I tend to prefer ranges as well, but iterators don't cause bloat.   
Just have something like this:

   template <typename iter>
   ... create(iter start, iter end) {
     if (start != end)
       return create(&*start, end-start);
     return create(0,0);
   }

which inlines away.  This requires the iterators to be sequential in  
memory, which is perfectly reasonable IMO.

-Chris