isBidirectionalRange

Returns true if R is a bidirectional range. A bidirectional range is a forward range that also offers the primitives back and popBack. The following code should compile for any bidirectional range.

The semantics of a bidirectional range (not checkable during compilation) are assumed to be the following (r is an object of type R):

r.back returns (possibly a reference to) the last element in the range. Calling r.back is allowed only if calling r.empty has, or would have, returned false.

enum bool isBidirectionalRange(R);

Examples

alias R = int[];
R r = [0,1];
static assert(isForwardRange!R);           // is forward range
r.popBack();                               // can invoke popBack
auto t = r.back;                           // can get the back of the range
auto w = r.front;
static assert(is(typeof(t) == typeof(w))); // same type for front and back

isBidirectionalRange

Examples

See Also

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