ceph/src/boost/libs/mpl/doc/src/refmanual/single_view.rst

   1 .. Sequences/Views//single_view
   2
   3 single_view
   4 ===========
   5
   6 Synopsis
   7 --------
   8
   9 .. parsed-literal::
  10
  11     template<
  12           typename T
  13         >
  14     struct single_view
  15     {
  16         // |unspecified|
  17         // |...|
  18     };
  19
  20
  21
  22 Description
  23 -----------
  24
  25 A view onto an arbitrary type ``T`` as on a single-element sequence.
  26
  27
  28 Header
  29 ------
  30
  31 .. parsed-literal::
  32
  33     #include <boost/mpl/single_view.hpp>
  34
  35
  36 Model of
  37 --------
  38
  39 * |Random Access Sequence|
  40
  41
  42 Parameters
  43 ----------
  44
  45 +---------------+-------------------+-----------------------------------------------+
  46 | Parameter     | Requirement       | Description                                   |
  47 +===============+===================+===============================================+
  48 | ``T``         | Any type          | The type to be wrapped in a sequence.         |
  49 +---------------+-------------------+-----------------------------------------------+
  50
  51
  52 Expression semantics
  53 --------------------
  54
  55 |Semantics disclaimer...| |Random Access Sequence|.
  56
  57 In the following table, ``v`` is an instance of ``single_view``, ``x`` is an arbitrary type.
  58
  59 +-------------------------------+-----------------------------------------------------------+
  60 | Expression                    | Semantics                                                 |
  61 +===============================+===========================================================+
  62 | .. parsed-literal::           | A single-element |Random Access Sequence| ``v`` such that |
  63 |                               | ``front<v>::type`` is identical to ``x``.                 |
  64 |    single_view<x>             |                                                           |
  65 |    single_view<x>::type       |                                                           |
  66 +-------------------------------+-----------------------------------------------------------+
  67 | ``size<v>::type``             | The size of ``v``; ``size<v>::value == 1``;               |
  68 |                               | see |Random Access Sequence|.                             |
  69 +-------------------------------+-----------------------------------------------------------+
  70
  71 Example
  72 -------
  73
  74 .. parsed-literal::
  75
  76     typedef single_view<int> view;
  77     typedef begin<view>::type first;
  78     typedef end<view>::type last;
  79
  80     BOOST_MPL_ASSERT(( is_same< deref<first>::type,int > ));
  81     BOOST_MPL_ASSERT(( is_same< next<first>::type,last > ));
  82     BOOST_MPL_ASSERT(( is_same< prior<last>::type,first > ));
  83
  84     BOOST_MPL_ASSERT_RELATION( size<view>::value, ==, 1 );
  85
  86
  87 See also
  88 --------
  89
  90 |Sequences|, |Views|, |iterator_range|, |filter_view|, |transform_view|, |joint_view|, |zip_view|
  91
  92
  93 .. copyright:: Copyright ©  2001-2009 Aleksey Gurtovoy and David Abrahams
  94    Distributed under the Boost Software License, Version 1.0. (See accompanying
  95    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)