rollup of small-medium size pulls

[thestinger]

f0f4dcc r=huonw
25e9c4c r=graydon
a87c2d1 r=brson
16f369d r=cmr
9f05cc8 r=bstrie
e858055 r=huonw
5d80938 r=thestinger
05d03e7 r=cmr
8f86fa3 r=thestinger

[alexcrichton]

I can see the need for something like this, but I'm a bit confused on the actual wording. It's called RandomAccessIterator, but nothing is being iterated over? It seems like this is simply another version of the Index trait with a size method. Morally speaking, it seems RandomAccessIterator == Index + Container, so should it possibly be renamed or derived from other names? I also can't think of a compelling use case for this, so I'm sure I'm missing something big. Is this meant to generalize something like a sorting algorithm over a container like a deque/array?

Also, cc #7766

[thestinger]

@alexcrichton: The Container trait doesn't work for this because the len method is the actual length, and iterators can be larger than a uint or even infinite. The Index trait is going to be removed (#6515) so I don't want to make any more code depending on it. It needs to be replaced before it can be used for this, and it's not certain it will be usable because it will have to make assumptions about mutability to replicate the vector syntax.

Random access iterators will allow generic algorithms (like sort or binary search) to work on any random access iterator, not just containers. For example you'll be able to chain together 2 vectors and a deque and sort them as a single range of values.

[omasanori]

There is a bikeshed: iterator vs range, right?

Although random access iterators are not really iterators IHMO, C++ has been called them iterators for a long time... (I don't think Rust must use C++ term instead of dlang term. It's just an example.)

[thestinger]

@omasanori: it's not really the C++ term, languages like Python use the term iterator for what D calls an InputRange

[omasanori]

@thestinger yes, you are right.

[dotdash]

Fixed version of my PR that failed to test on windows: https://github.com/dotdash/rust/commits/transmute_ice