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

   1 .. Algorithms/Querying Algorithms//contains |30
   2
   3 contains
   4 ========
   5
   6 Synopsis
   7 --------
   8
   9 .. parsed-literal::
  10
  11     template<
  12           typename Sequence
  13         , typename T
  14         >
  15     struct contains
  16     {
  17         typedef |unspecified| type;
  18     };
  19
  20
  21
  22 Description
  23 -----------
  24
  25 Returns a true-valued |Integral Constant| if one or more elements in ``Sequence``
  26 are identical to ``T``.
  27
  28
  29 Header
  30 ------
  31
  32 .. parsed-literal::
  33
  34     #include <boost/mpl/contains.hpp>
  35
  36
  37 Parameters
  38 ----------
  39
  40 +---------------+---------------------------+-----------------------------------+
  41 | Parameter     | Requirement               | Description                       |
  42 +===============+===========================+===================================+
  43 | ``Sequence``  | |Forward Sequence|        | A sequence to be examined.        |
  44 +---------------+---------------------------+-----------------------------------+
  45 | ``T``         | Any type                  | A type to search for.             |
  46 +---------------+---------------------------+-----------------------------------+
  47
  48
  49 Expression semantics
  50 --------------------
  51
  52 For any |Forward Sequence| ``s`` and arbitrary type ``t``:
  53
  54
  55 .. parsed-literal::
  56
  57     typedef contains<s,t>::type r;
  58
  59
  60 :Return type:
  61     |Integral Constant|.
  62
  63 :Semantics:
  64     Equivalent to
  65
  66     .. parsed-literal::
  67
  68         typedef not_< is_same<
  69               find<s,t>::type
  70             , end<s>::type
  71             > >::type r;
  72
  73
  74 Complexity
  75 ----------
  76
  77 Linear. At most ``size<s>::value`` comparisons for identity.
  78
  79
  80 Example
  81 -------
  82
  83 .. parsed-literal::
  84
  85     typedef vector<char,int,unsigned,long,unsigned long> types;
  86     BOOST_MPL_ASSERT_NOT(( contains<types,bool> ));
  87
  88
  89 See also
  90 --------
  91
  92 |Querying Algorithms|, |find|, |find_if|, |count|, |lower_bound|
  93
  94
  95 .. copyright:: Copyright ©  2001-2009 Aleksey Gurtovoy and David Abrahams
  96    Distributed under the Boost Software License, Version 1.0. (See accompanying
  97    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)