| .. Sequences/Intrinsic Metafunctions//is_sequence |
| |
| is_sequence |
| =========== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename X |
| > |
| struct is_sequence |
| { |
| typedef |unspecified| type; |
| }; |
| |
| |
| |
| Description |
| ----------- |
| |
| Returns a boolean |Integral Constant| ``c`` such that ``c::value == true`` if and |
| only if ``X`` is a model of |Forward Sequence|. |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/is_sequence.hpp> |
| |
| |
| Parameters |
| ---------- |
| |
| +---------------+-------------------+-----------------------------------------------+ |
| | Parameter | Requirement | Description | |
| +===============+===================+===============================================+ |
| | ``X`` | Any type | The type to query. | |
| +---------------+-------------------+-----------------------------------------------+ |
| |
| |
| Expression semantics |
| -------------------- |
| |
| |
| .. parsed-literal:: |
| |
| typedef is_sequence<X>::type c; |
| |
| :Return type: |
| Boolean |Integral Constant|. |
| |
| :Semantics: |
| Equivalent to |
| |
| .. parsed-literal:: |
| |
| typedef not_< is_same< begin<T>::type,void_ > >::type c; |
| |
| |
| |
| Complexity |
| ---------- |
| |
| Amortized constant time. |
| |
| |
| Example |
| ------- |
| |
| .. parsed-literal:: |
| |
| struct UDT {}; |
| |
| BOOST_MPL_ASSERT_NOT(( is_sequence< std::vector<int> > )); |
| BOOST_MPL_ASSERT_NOT(( is_sequence< int > )); |
| BOOST_MPL_ASSERT_NOT(( is_sequence< int& > )); |
| BOOST_MPL_ASSERT_NOT(( is_sequence< UDT > )); |
| BOOST_MPL_ASSERT_NOT(( is_sequence< UDT* > )); |
| BOOST_MPL_ASSERT(( is_sequence< range_c<int,0,0> > )); |
| BOOST_MPL_ASSERT(( is_sequence< list<> > )); |
| BOOST_MPL_ASSERT(( is_sequence< list<int> > )); |
| BOOST_MPL_ASSERT(( is_sequence< vector<> > )); |
| BOOST_MPL_ASSERT(( is_sequence< vector<int> > )); |
| |
| |
| See also |
| -------- |
| |
| |Forward Sequence|, |begin|, |end|, |vector|, |list|, |range_c| |
| |
| |
| .. copyright:: Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
