projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Metafunctions/Invocation//unpack_args |30 |
| 2 | ||
| 3 | unpack_args | |
| 4 | =========== | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | template< | |
| 12 | typename F | |
| 13 | > | |
| 14 | struct unpack_args | |
| 15 | { | |
| 16 | // |unspecified| | |
| 17 | // |...| | |
| 18 | }; | |
| 19 | ||
| 20 | ||
| 21 | Description | |
| 22 | ----------- | |
| 23 | ||
| 24 | A higher-order primitive transforming an *n*-ary |Lambda Expression| ``F`` into | |
| 25 | an unary |Metafunction Class| ``g`` accepting a single sequence of *n* arguments. | |
| 26 | ||
| 27 | ||
| 28 | Header | |
| 29 | ------ | |
| 30 | ||
| 31 | .. parsed-literal:: | |
| 32 | ||
| 33 | #include <boost/mpl/unpack_args.hpp> | |
| 34 | ||
| 35 | ||
| 36 | Model of | |
| 37 | -------- | |
| 38 | ||
| 39 | |Metafunction Class| | |
| 40 | ||
| 41 | ||
| 42 | Parameters | |
| 43 | ---------- | |
| 44 | ||
| 45 | +---------------+-----------------------+-------------------------------------------+ | |
| 46 | | Parameter | Requirement | Description | | |
| 47 | +===============+=======================+===========================================+ | |
| 48 | | ``F`` | |Lambda Expression| | A lambda expression to adopt. | | |
| 49 | +---------------+-----------------------+-------------------------------------------+ | |
| 50 | ||
| 51 | ||
| 52 | Expression semantics | |
| 53 | -------------------- | |
| 54 | ||
| 55 | For an arbitrary |Lambda Expression| ``f``, and arbitrary types |a1...an|: | |
| 56 | ||
| 57 | ||
| 58 | .. parsed-literal:: | |
| 59 | ||
| 60 | typedef unpack_args<f> g; | |
| 61 | ||
| 62 | :Return type: | |
| 63 | |Metafunction Class|. | |
| 64 | ||
| 65 | :Semantics: | |
| 66 | ``g`` is a unary |Metafunction Class| such that | |
| 67 | ||
| 68 | .. parsed-literal:: | |
| 69 | ||
| 70 | apply_wrap\ *n*\ < g, vector<a1,\ |...|\ a\ *n*\ > >::type | |
| 71 | ||
| 72 | is identical to | |
| 73 | ||
| 74 | .. parsed-literal:: | |
| 75 | ||
| 76 | apply<F,a1,\ |...|\ a\ *n*\ >::type | |
| 77 | ||
| 78 | ||
| 79 | Example | |
| 80 | ------- | |
| 81 | ||
| 82 | .. parsed-literal:: | |
| 83 | ||
| 84 | BOOST_MPL_ASSERT(( apply< | |
| 85 | unpack_args< is_same<_1,_2> > | |
| 86 | , vector<int,int> | |
| 87 | > )); | |
| 88 | ||
| 89 | ||
| 90 | See also | |
| 91 | -------- | |
| 92 | ||
| 93 | |Metafunctions|, |Lambda Expression|, |Metafunction Class|, |apply|, |apply_wrap|, |bind| | |
| 94 | ||
| 95 | ||
| 96 |