projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
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 |