Adds an explicit @escaping throughout the standard library, validation
test suite, and tests. This will be necessary as soon as noescape is
the default for closure parameters.
...replacing it with the new, after passing API review!
* The lazy free function has become a property.
* Before we could extend protocols, we lacked a means for value types to
share implementations, and each new lazy algorithm had to be added to
each of up to four types: LazySequence, LazyForwardCollection,
LazyBidirectionalCollection, and LazyRandomAccessCollection. These
generic adapters hid the usual algorithms by defining their own
versions that returned new lazy generic adapters. Now users can extend
just one of two protocols to do the same thing: LazySequenceType or
LazyCollectionType.
* To avoid making the code duplication worse than it already was, the
generic adapters mentioned above were used to add the lazy generic
algorithms around simpler adapters such as MapSequence that just
provided the basic requirements of SequenceType by applying a
transformation to some base sequence, resulting in deeply nested
generic types as shown here. Now, MapSequence is an instance of
LazySequenceType (and is renamed LazyMapSequence), and thus transmits
laziness to its algorithms automatically.
* Documentation comments have been rewritten.
* The .array property was retired
* various renamings
* A bunch of Gyb files were retired.
Swift SVN r30902
An index of a FlattenCollection is composed of two: an index to the
current chunk and an index within that chunk. So you take the
startIndex, and advance it to the second chunk; call the result idx1.
You take startIndex again, and advance it the same number of steps; call
the result idx2:
let idx1 = flatMapCollection.startIndex.advancedBy(10)
let idx2 = flatMapCollection.startIndex.advancedBy(10)
idx1 and idx2 have to compare equal according to collection and index
axioms. But this can't be cheaply implemented. Every index contains an
index into the inner collection. So indices into two collections with
the same elements have to compare equal even though the collections
don't have any common history, they were merely created using the same
sequence of steps.
What currently happens is that you get random results depending on the
underlying collection kind.
rdar://21989896
Swift SVN r30617
