| .. Sequences/Intrinsic Metafunctions//erase |
| |
| erase |
| ===== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename Sequence |
| , typename First |
| , typename Last = |unspecified| |
| > |
| struct erase |
| { |
| typedef |unspecified| type; |
| }; |
| |
| |
| |
| Description |
| ----------- |
| |
| ``erase`` performs a removal of one or more adjacent elements in the sequence |
| starting from an arbitrary position. |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/erase.hpp> |
| |
| |
| Model of |
| -------- |
| |
| |Tag Dispatched Metafunction| |
| |
| |
| Parameters |
| ---------- |
| |
| +---------------+-----------------------------------+-----------------------------------------------+ |
| | Parameter | Requirement | Description | |
| +===============+===================================+===============================================+ |
| | ``Sequence`` | |Extensible Sequence| or | A sequence to erase from. | |
| | | |Extensible Associative Sequence| | | |
| +---------------+-----------------------------------+-----------------------------------------------+ |
| | ``First`` | |Forward Iterator| | An iterator to the beginning of the range to | |
| | | | be erased. | |
| +---------------+-----------------------------------+-----------------------------------------------+ |
| | ``Last`` | |Forward Iterator| | An iterator past-the-end of the range to be | |
| | | | erased. | |
| +---------------+-----------------------------------+-----------------------------------------------+ |
| |
| |
| Expression semantics |
| -------------------- |
| |
| .. compound:: |
| :class: expression-semantics |
| |
| For any |Extensible Sequence| ``s``, and iterators ``pos``, ``first`` and ``last`` into ``s``: |
| |
| |
| .. parsed-literal:: |
| |
| typedef erase<s,first,last>::type r; |
| |
| :Return type: |
| |Extensible Sequence|. |
| |
| :Precondition: |
| ``[first,last)`` is a valid range in ``s``. |
| |
| :Semantics: |
| ``r`` is a new sequence, |concept-identical| to ``s``, of the following elements: |
| [``begin<s>::type``, ``pos``), [``last``, ``end<s>::type``). |
| |
| :Postcondition: |
| The relative order of the elements in ``r`` is the same as in ``s``; |
| |
| .. parsed-literal:: |
| |
| size<r>::value == size<s>::value - distance<first,last>::value |
| |
| |
| .. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| .. parsed-literal:: |
| |
| typedef erase<s,pos>::type r; |
| |
| :Return type: |
| |Extensible Sequence|. |
| |
| :Precondition: |
| ``pos`` is a dereferenceable iterator in ``s``. |
| |
| :Semantics: |
| Equivalent to |
| |
| .. parsed-literal:: |
| |
| typedef erase< s,pos,next<pos>::type >::type r; |
| |
| |
| |
| .. compound:: |
| :class: expression-semantics |
| |
| For any |Extensible Associative Sequence| ``s``, and iterator ``pos`` into ``s``: |
| |
| .. parsed-literal:: |
| |
| typedef erase<s,pos>::type r; |
| |
| :Return type: |
| |Extensible Sequence|. |
| |
| :Precondition: |
| ``pos`` is a dereferenceable iterator to ``s``. |
| |
| :Semantics: |
| Erases the element at a specific position ``pos``; equivalent to |
| ``erase_key<s, deref<pos>::type >::type``. |
| |
| :Postcondition: |
| ``size<r>::value == size<s>::value - 1``. |
| |
| |
| Complexity |
| ---------- |
| |
| +---------------------------------------+-----------------------------------------------+ |
| | Sequence archetype | Complexity (the range form) | |
| +=======================================+===============================================+ |
| | |Extensible Associative Sequence| | Amortized constant time. | |
| +---------------------------------------+-----------------------------------------------+ |
| | |Extensible Sequence| | Quadratic in the worst case, linear at best. | |
| +---------------------------------------+-----------------------------------------------+ |
| |
| |
| Example |
| ------- |
| |
| .. parsed-literal:: |
| |
| typedef vector_c<int,1,0,5,1,7,5,0,5> values; |
| typedef find< values, integral_c<int,7> >::type pos; |
| typedef erase<values,pos>::type result; |
| |
| BOOST_MPL_ASSERT_RELATION( size<result>::value, ==, 7 ); |
| |
| typedef find<result, integral_c<int,7> >::type iter; |
| BOOST_MPL_ASSERT(( is_same< iter, end<result>::type > )); |
| |
| |
| See also |
| -------- |
| |
| |Extensible Sequence|, |Extensible Associative Sequence|, |erase_key|, |pop_front|, |pop_back|, |insert| |
| |
| |
| .. 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) |