protocol ReverseIndexType
Inheritance |
BidirectionalIndexType, Equatable, ForwardIndexType, _Incrementable
View Protocol Hierarchy →
|
---|---|
Associated Types | |
Import | import Swift |
Initializers
Instance Variables
The successor position in the underlying (un-reversed) collection.
If self
is advance(c.reverse.startIndex, n)
, then:
- self.base
is advance(c.endIndex, -n)
.
- if n
!= c.count
, then c.reverse[self]
is
equivalent to [self.base.predecessor()]
.
Declaration
var base: Self.Base { get }
Instance Methods
Returns true
if lhs
is equal to rhs
.
Equality implies substitutability. When x == y
, x
and
y
are interchangeable in any code that only depends on their
values.
Class instance identity as distinguished by triple-equals ===
is notably not part of an instance's value. Exposing other
non-value aspects of Equatable
types is discouraged, and any
that are exposed should be explicitly pointed out in
documentation.
Equality is an equivalence relation
x == x
istrue
x == y
impliesy == x
x == y
andy == z
impliesx == z
Inequality is the inverse of equality, i.e. !(x == y)
iff
x != y
.
Declaration
func ==(lhs: Self, rhs: Self) -> Bool
Declared In
Equatable
Returns the result of advancing self
by n
positions.
Returns:
- If n > 0
, the result of applying successor
to self
n
times.
- If n < 0
, the result of applying predecessor
to self
-n
times.
- Otherwise, self
.
Requires: n >= 0
if only conforming to ForwardIndexType
Complexity:
- O(1) if conforming to RandomAccessIndexType
- O(abs(n)
) otherwise
Declaration
func advancedBy(n: Self.Distance) -> Self
Declared In
ForwardIndexType
Returns the result of advancing self
by n
positions, or until it
equals limit
.
Returns:
- If n > 0
, the result of applying successor
to self
n
times
but not past limit
.
- If n < 0
, the result of applying predecessor
to self
-n
times
but not past limit
.
- Otherwise, self
.
Requires: n >= 0
if only conforming to ForwardIndexType
.
Complexity:
- O(1) if conforming to RandomAccessIndexType
- O(abs(n)
) otherwise
Declaration
func advancedBy(n: Self.Distance, limit: Self) -> Self
Declared In
ForwardIndexType
Measure the distance between self
and end
.
Requires:
- start
and end
are part of the same sequence when conforming to
RandomAccessSequenceType
.
- end
is reachable from self
by incrementation otherwise.
Complexity:
- O(1) if conforming to RandomAccessIndexType
- O(n
) otherwise, where n
is the function's result.
Declaration
func distanceTo(end: Self) -> Self.Distance
Declared In
ForwardIndexType
Returns the previous consecutive value in a discrete sequence.
If self
has a well-defined successor,
self.successor().predecessor() == self
. If self
has a
well-defined predecessor, self.predecessor().successor() ==
self
.
Requires: self
has a well-defined predecessor.
Declaration
func predecessor() -> Self
Declared In
BidirectionalIndexType
Returns the next consecutive value in a discrete sequence of
Self
values.
Requires: self
has a well-defined successor.
Declaration
func successor() -> Self
Declared In
_Incrementable
Default Implementations
Returns the result of advancing self
by n
positions.
Returns:
- If n > 0
, the result of applying successor
to self
n
times.
- If n < 0
, the result of applying predecessor
to self
-n
times.
- Otherwise, self
.
Requires: n >= 0
if only conforming to ForwardIndexType
Complexity:
- O(1) if conforming to RandomAccessIndexType
- O(abs(n)
) otherwise
Declaration
func advancedBy(n: Self.Distance) -> Self
Declared In
BidirectionalIndexType
, ForwardIndexType
Returns the result of advancing self
by n
positions, or until it
equals limit
.
Returns:
- If n > 0
, the result of applying successor
to self
n
times
but not past limit
.
- If n < 0
, the result of applying predecessor
to self
-n
times
but not past limit
.
- Otherwise, self
.
Requires: n >= 0
if only conforming to ForwardIndexType
.
Complexity:
- O(1) if conforming to RandomAccessIndexType
- O(abs(n)
) otherwise
Declaration
func advancedBy(n: Self.Distance, limit: Self) -> Self
Declared In
BidirectionalIndexType
, ForwardIndexType
Measure the distance between self
and end
.
Requires:
- start
and end
are part of the same sequence when conforming to
RandomAccessSequenceType
.
- end
is reachable from self
by incrementation otherwise.
Complexity:
- O(1) if conforming to RandomAccessIndexType
- O(n
) otherwise, where n
is the function's result.
Declaration
func distanceTo(end: Self) -> Self.Distance
Declared In
BidirectionalIndexType
, ForwardIndexType
An index that traverses the same positions as an underlying index, with inverted traversal direction.