projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Algorithms/Transformation Algorithms//replace_if |50 |
| 2 | ||
| 3 | replace_if | |
| 4 | ========== | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | template< | |
| 12 | typename Sequence | |
| 13 | , typename Pred | |
| 14 | , typename NewType | |
| 15 | , typename In = |unspecified| | |
| 16 | > | |
| 17 | struct replace_if | |
| 18 | { | |
| 19 | typedef |unspecified| type; | |
| 20 | }; | |
| 21 | ||
| 22 | ||
| 23 | ||
| 24 | Description | |
| 25 | ----------- | |
| 26 | ||
| 27 | Returns a copy of the original sequence where every type that satisfies | |
| 28 | the predicate ``Pred`` has been replaced with ``NewType``. | |
| 29 | ||
| 30 | |transformation algorithm disclaimer| | |
| 31 | ||
| 32 | Header | |
| 33 | ------ | |
| 34 | ||
| 35 | .. parsed-literal:: | |
| 36 | ||
| 37 | #include <boost/mpl/replace_if.hpp> | |
| 38 | ||
| 39 | ||
| 40 | ||
| 41 | Model of | |
| 42 | -------- | |
| 43 | ||
| 44 | |Reversible Algorithm| | |
| 45 | ||
| 46 | ||
| 47 | Parameters | |
| 48 | ---------- | |
| 49 | ||
| 50 | +---------------+-----------------------------------+-------------------------------+ | |
| 51 | | Parameter | Requirement | Description | | |
| 52 | +===============+===================================+===============================+ | |
| 53 | | ``Sequence`` | |Forward Sequence| | An original sequence. | | |
| 54 | +---------------+-----------------------------------+-------------------------------+ | |
| 55 | | ``Pred`` | Unary |Lambda Expression| | A replacement condition. | | |
| 56 | +---------------+-----------------------------------+-------------------------------+ | |
| 57 | | ``NewType`` | Any type | A type to replace with. | | |
| 58 | +---------------+-----------------------------------+-------------------------------+ | |
| 59 | | ``In`` | |Inserter| | An inserter. | | |
| 60 | +---------------+-----------------------------------+-------------------------------+ | |
| 61 | ||
| 62 | ||
| 63 | Expression semantics | |
| 64 | -------------------- | |
| 65 | ||
| 66 | |Semantics disclaimer...| |Reversible Algorithm|. | |
| 67 | ||
| 68 | For any |Forward Sequence| ``s``, an unary |Lambda Expression| ``pred``, | |
| 69 | an |Inserter| ``in``, and arbitrary type ``x``: | |
| 70 | ||
| 71 | ||
| 72 | .. parsed-literal:: | |
| 73 | ||
| 74 | typedef replace_if<s,pred,x,in>::type r; | |
| 75 | ||
| 76 | :Return type: | |
| 77 | A type. | |
| 78 | ||
| 79 | :Semantics: | |
| 80 | Equivalent to | |
| 81 | ||
| 82 | .. parsed-literal:: | |
| 83 | ||
| 84 | typedef lambda<pred>::type p; | |
| 85 | typedef transform< s, if_< apply_wrap1<p,_1>,x,_1>, in >::type r; | |
| 86 | ||
| 87 | ||
| 88 | Complexity | |
| 89 | ---------- | |
| 90 | ||
| 91 | Linear. Performs exactly ``size<s>::value`` applications of ``pred``, and at most | |
| 92 | ``size<s>::value`` insertions. | |
| 93 | ||
| 94 | ||
| 95 | Example | |
| 96 | ------- | |
| 97 | ||
| 98 | .. parsed-literal:: | |
| 99 | ||
| 100 | typedef vector_c<int,1,4,5,2,7,5,3,5> numbers; | |
| 101 | typedef vector_c<int,1,4,0,2,0,0,3,0> expected; | |
| 102 | typedef replace_if< numbers, greater<_,int_<4> >, int_<0> >::type result; | |
| 103 | ||
| 104 | BOOST_MPL_ASSERT(( equal< result,expected, equal_to<_,_> > )); | |
| 105 | ||
| 106 | ||
| 107 | See also | |
| 108 | -------- | |
| 109 | ||
| 110 | |Transformation Algorithms|, |Reversible Algorithm|, |reverse_replace_if|, |replace|, |remove_if|, |transform| | |
| 111 | ||
| 112 | ||
| 113 |