The MPL Reference Manual: prior

prior

Synopsis

template<
      typename Iterator
    >
struct prior
{
    typedef unspecified type;
};

Returns the previous iterator in the sequence. [Note: prior has a number of overloaded meanings, depending on the type of its argument. For instance, if X is an Integral Constant, prior returns an decremented Integral Constant of the same type. The following specification is iterator-specific. Please refer to the corresponding concept's documentation for the details of the alternative semantics — end note].

Header

#include <boost/mpl/next_prior.hpp>

Parameters

Parameter	Requirement	Description
`Iterator`	Bidirectional Iterator.	An iterator to decrement.

Expression semantics

For any Bidirectional Iterators iter:

typedef prior::type j;

Return type:

Return type:	Bidirectional Iterator.
Precondition:	`iter` is decrementable.
Semantics:	`j` is an iterator pointing to the previous element in the sequence. If `iter` is a user-defined iterator, the library-provided default implementation is equivalent to typedef iter::prior j;

Bidirectional Iterator.

Precondition:

iter is decrementable.

Semantics:

j is an iterator pointing to the previous element in the sequence. If iter is a user-defined iterator, the library-provided default implementation is equivalent to

typedef iter::prior j;

Complexity

Amortized constant time.

Example

typedef vector_c v;
typedef begin::type first;
typedef end::type last;

BOOST_MPL_ASSERT(( is_same< prior::type, first > ));

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