The MPL Reference Manual: single_view

single_view

Synopsis

template<
      typename T
    >
struct single_view
{
    // unspecified
    // ...
};

Description

A view onto an arbitrary type T as on a single-element sequence.

Header

#include <boost/mpl/single_view.hpp>

Model of

Random Access Sequence

Parameters

Parameter	Requirement	Description
`T`	Any type	The type to be wrapped in a sequence.

Expression semantics

The semantics of an expression are defined only where they differ from, or are not defined in Random Access Sequence.

In the following table, v is an instance of single_view, x is an arbitrary type.

Expression	Semantics
single_view single_view::type	A single-element Random Access Sequence `v` such that `front::type` is identical to `x`.
`size::type`	The size of `v`; `size::value == 1`; see Random Access Sequence.

Example

typedef single_view view;
typedef begin::type first;
typedef end::type last;

BOOST_MPL_ASSERT(( is_same< deref::type,int > ));
BOOST_MPL_ASSERT(( is_same< next::type,last > ));
BOOST_MPL_ASSERT(( is_same< prior::type,first > ));

BOOST_MPL_ASSERT_RELATION( size::value, ==, 1 );

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