| .. Sequences/Views//single_view |
| |
| single_view |
| =========== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename T |
| > |
| struct single_view |
| { |
| // |unspecified| |
| // |...| |
| }; |
| |
| |
| |
| Description |
| ----------- |
| |
| A view onto an arbitrary type ``T`` as on a single-element sequence. |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #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 |
| -------------------- |
| |
| |Semantics disclaimer...| |Random Access Sequence|. |
| |
| In the following table, ``v`` is an instance of ``single_view``, ``x`` is an arbitrary type. |
| |
| +-------------------------------+-----------------------------------------------------------+ |
| | Expression | Semantics | |
| +===============================+===========================================================+ |
| | .. parsed-literal:: | A single-element |Random Access Sequence| ``v`` such that | |
| | | ``front<v>::type`` is identical to ``x``. | |
| | single_view<x> | | |
| | single_view<x>::type | | |
| +-------------------------------+-----------------------------------------------------------+ |
| | ``size<v>::type`` | The size of ``v``; ``size<v>::value == 1``; | |
| | | see |Random Access Sequence|. | |
| +-------------------------------+-----------------------------------------------------------+ |
| |
| Example |
| ------- |
| |
| .. parsed-literal:: |
| |
| typedef single_view<int> view; |
| typedef begin<view>::type first; |
| typedef end<view>::type last; |
| |
| BOOST_MPL_ASSERT(( is_same< deref<first>::type,int > )); |
| BOOST_MPL_ASSERT(( is_same< next<first>::type,last > )); |
| BOOST_MPL_ASSERT(( is_same< prior<last>::type,first > )); |
| |
| BOOST_MPL_ASSERT_RELATION( size<view>::value, ==, 1 ); |
| |
| |
| See also |
| -------- |
| |
| |Sequences|, |Views|, |iterator_range|, |filter_view|, |transform_view|, |joint_view|, |zip_view| |
| |
| |
| .. copyright:: Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
