Should std.algorithm.find demand a reference to range elements?

[Jakob Ovrum via Digitalmars-d]

On Thursday, 5 February 2015 at 10:36:34 UTC, Eduardo Pinho wrote:
> Some assistance on understanding what is wrong here is greatly 
> appreciated.

There's definitely nothing wrong with your code.

I always thought foreach preferred opApply when available because 
internal iteration can in theory be faster than external 
iteration (although it rarely is with current compilers because 
the indirect call to the delegate is often the bottleneck), but 
as you've pointed out, the specification claims external 
iteration is be preferred. Either the specification has to be 
changed, or the compiler has to be changed.

If internal iteration remains preferred, `find` should probably 
be changed to use an explicit for-loop:
---
     size_t i = 0;
     for (auto h = haystack.save; !h.empty; h.popFront())
     {
         if (predFun(h.front))
             return haystack[i .. $];
         ++i;
     }
     return haystack[$ .. $];
---
(`haystack` is known to be a forward range in this portion of the 
code)

However, this would set a possibly disruptive precedent that 
range algorithms must no longer use foreach on aggregate types...