| .. Algorithms/Transformation Algorithms//transform |30 |
| |
| transform |
| ========= |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename Sequence |
| , typename Op |
| , typename In = |unspecified| |
| > |
| struct transform |
| { |
| typedef |unspecified| type; |
| }; |
| |
| template< |
| typename Seq1 |
| , typename Seq2 |
| , typename BinaryOp |
| , typename In = |unspecified| |
| > |
| struct transform |
| { |
| typedef |unspecified| type; |
| }; |
| |
| |
| Description |
| ----------- |
| |
| ``transform`` is an |overloaded name|: |
| |
| * ``transform<Sequence,Op>`` returns a transformed copy of the original sequence |
| produced by applying an unary transformation ``Op`` to every element |
| in the |begin/end<Sequence>| range. |
| |
| * ``transform<Seq1,Seq2,BinaryOp>`` returns a new sequence produced by applying a |
| binary transformation ``BinaryOp`` to a pair of elements (e\ :sub:`1`, e2\ :sub:`1`) |
| from the corresponding |begin/end<Seq1>| and |begin/end<Seq2>| ranges. |
| |
| |transformation algorithm disclaimer| |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/transform.hpp> |
| |
| |
| Model of |
| -------- |
| |
| |Reversible Algorithm| |
| |
| |
| Parameters |
| ---------- |
| |
| +-------------------+-----------------------------------+-----------------------------------+ |
| | Parameter | Requirement | Description | |
| +===================+===================================+===================================+ |
| | ``Sequence``, | |Forward Sequence| | Sequences to transform. | |
| | ``Seq1``, ``Seq2``| | | |
| +-------------------+-----------------------------------+-----------------------------------+ |
| | ``Op``, | |Lambda Expression| | A transformation. | |
| | ``BinaryOp`` | | | |
| +-------------------+-----------------------------------+-----------------------------------+ |
| | ``In`` | |Inserter| | An inserter. | |
| +-------------------+-----------------------------------+-----------------------------------+ |
| |
| |
| Expression semantics |
| -------------------- |
| |
| |Semantics disclaimer...| |Reversible Algorithm|. |
| |
| For any |Forward Sequence|\ s ``s``, ``s1`` and ``s2``, |Lambda Expression|\ s ``op`` and ``op2``, |
| and an |Inserter| ``in``: |
| |
| .. parsed-literal:: |
| |
| typedef transform<s,op,in>::type r; |
| |
| :Return type: |
| A type. |
| |
| :Postcondition: |
| Equivalent to |
| |
| .. parsed-literal:: |
| |
| typedef lambda<op>::type f; |
| typedef lambda<in::operation>::type in_op; |
| |
| typedef fold< |
| s |
| , in::state |
| , bind< in_op, _1, bind<f, _2> > |
| >::type r; |
| |
| |
| .. parsed-literal:: |
| |
| typedef transform<s1,s2,op,in>::type r; |
| |
| :Return type: |
| A type. |
| |
| :Postcondition: |
| Equivalent to |
| |
| .. parsed-literal:: |
| |
| typedef lambda<op2>::type f; |
| typedef lambda<in::operation>::type in_op; |
| |
| typedef fold< |
| pair_view<s1,s2> |
| , in::state |
| , bind< |
| in_op |
| , _1 |
| , bind<f, bind<first<>,_2>, bind<second<>,_2> > |
| > |
| >::type r; |
| |
| |
| Complexity |
| ---------- |
| |
| Linear. Exactly ``size<s>::value`` / ``size<s1>::value`` applications of |
| ``op`` / ``op2`` and ``in::operation``. |
| |
| |
| Example |
| ------- |
| |
| .. parsed-literal:: |
| |
| typedef vector<char,short,int,long,float,double> types; |
| typedef vector<char*,short*,int*,long*,float*,double*> pointers; |
| typedef transform< types,boost::add_pointer<_1> >::type result; |
| |
| BOOST_MPL_ASSERT(( equal<result,pointers> )); |
| |
| |
| See also |
| -------- |
| |
| |Transformation Algorithms|, |Reversible Algorithm|, |reverse_transform|, |copy|, |replace_if| |
| |
| |
| .. 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) |
