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

   1 .. Sequences/Views//transform_view
   2
   3 transform_view
   4 ==============
   5
   6 Synopsis
   7 --------
   8
   9 .. parsed-literal::
  10
  11     template<
  12           typename Sequence
  13         , typename F
  14         >
  15     struct transform_view
  16     {
  17         // |unspecified|
  18         // |...|
  19     };
  20
  21
  22 Description
  23 -----------
  24
  25 A view the full range of ``Sequence``\ 's transformed elements.
  26
  27
  28 Header
  29 ------
  30
  31 .. parsed-literal::
  32
  33     #include <boost/mpl/transform_view.hpp>
  34
  35
  36 Model of
  37 --------
  38
  39 * |Forward Sequence|
  40
  41
  42 Parameters
  43 ----------
  44
  45 +---------------+-------------------------------+-------------------------------+
  46 | Parameter     | Requirement                   | Description                   |
  47 +===============+===============================+===============================+
  48 | ``Sequence``  | |Forward Sequence|            | A sequence to wrap.           |
  49 +---------------+-------------------------------+-------------------------------+
  50 | ``F``         | Unary |Lambda Expression|     | A transformation.             |
  51 +---------------+-------------------------------+-------------------------------+
  52
  53
  54 Expression semantics
  55 --------------------
  56
  57 |Semantics disclaimer...| |Forward Sequence|.
  58
  59 In the following table, ``v`` is an instance of ``transform_view``, ``s`` is an arbitrary
  60 |Forward Sequence|, and ``f`` is an unary |Lambda Expression|.
  61
  62 +-----------------------------------+-----------------------------------------------------------+
  63 | Expression                        | Semantics                                                 |
  64 +===================================+===========================================================+
  65 | .. parsed-literal::               | A lazy |Forward Sequence| such that for each ``i`` in the |
  66 |                                   | range |begin/end<v>| and each ``j`` in for in the range   |
  67 |    transform_view<s,f>            | |begin/end<s>| ``deref<i>::type`` is identical to         |
  68 |    transform_view<s,f>::type      | ``apply< f, deref<j>::type >::type``.                     |
  69 +-----------------------------------+-----------------------------------------------------------+
  70 | ``size<v>::type``                 | The size of ``v``;                                        |
  71 |                                   | ``size<v>::value == size<s>::value``;                     |
  72 |                                   | linear complexity; see |Forward Sequence|.                |
  73 +-----------------------------------+-----------------------------------------------------------+
  74
  75
  76 Example
  77 -------
  78
  79 Find the largest type in a sequence.
  80
  81 .. parsed-literal::
  82
  83     typedef vector<int,long,char,char[50],double> types;
  84     typedef max_element<
  85           transform_view< types, size_of<_> >
  86         >::type iter;
  87
  88     BOOST_MPL_ASSERT_RELATION( deref<iter>::type::value, ==, 50 );
  89
  90
  91 See also
  92 --------
  93
  94 |Sequences|, |Views|, |filter_view|, |joint_view|, |zip_view|, |iterator_range|
  95
  96
  97 .. copyright:: Copyright ©  2001-2009 Aleksey Gurtovoy and David Abrahams
  98    Distributed under the Boost Software License, Version 1.0. (See accompanying
  99    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)