std::experimental::ranges::WeaklyIncrementable

Defined in header <experimental/ranges/iterator>
template < class I > concept bool WeaklyIncrementable =     Semiregular<I> &&     requires(I i) { typename ranges:: difference_type_t <I> ;         requires SignedIntegral<ranges:: difference_type_t <I>> ; { ++i } - > Same<I> & ; /* not required to be equality preserving */         i++ ; /* not required to be equality preserving */ } ;		(ranges TS)

The concept WeaklyIncrementable<I> specifies the requirements on a type that can be incremented (with the pre- and post-increment operators). The increment operations need not be equality-preserving, and the type need not be EqualityComparable

Let i be an object of type I. i is said to be incrementable if it is in the domain of both pre- and post-increment. WeaklyIncrementable<I>

• ++i and i++ have the same domain;
• If i is incrementable, then:
  • ++i and i++ both advance i
  • ++i refers to the same object as i.

Equality preservation

An expression is equality preserving if it results in equal outputs given equal inputs.

• The inputs to an expression consist of its operands.
• The outputs of an expression consist of its result and all operands modified by the expression (if any).

Every expression required to be equality preserving is further required to be stable

Notes

For WeaklyIncrementable types, a equals b does not imply that ++a equals ++b