| .. Sequences/Views//transform_view |
| |
| transform_view |
| ============== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename Sequence |
| , typename F |
| > |
| struct transform_view |
| { |
| // |unspecified| |
| // |...| |
| }; |
| |
| |
| Description |
| ----------- |
| |
| A view the full range of ``Sequence``\ 's transformed elements. |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/transform_view.hpp> |
| |
| |
| Model of |
| -------- |
| |
| * |Forward Sequence| |
| |
| |
| Parameters |
| ---------- |
| |
| +---------------+-------------------------------+-------------------------------+ |
| | Parameter | Requirement | Description | |
| +===============+===============================+===============================+ |
| | ``Sequence`` | |Forward Sequence| | A sequence to wrap. | |
| +---------------+-------------------------------+-------------------------------+ |
| | ``F`` | Unary |Lambda Expression| | A transformation. | |
| +---------------+-------------------------------+-------------------------------+ |
| |
| |
| Expression semantics |
| -------------------- |
| |
| |Semantics disclaimer...| |Forward Sequence|. |
| |
| In the following table, ``v`` is an instance of ``transform_view``, ``s`` is an arbitrary |
| |Forward Sequence|, and ``f`` is an unary |Lambda Expression|. |
| |
| +-----------------------------------+-----------------------------------------------------------+ |
| | Expression | Semantics | |
| +===================================+===========================================================+ |
| | .. parsed-literal:: | A lazy |Forward Sequence| such that for each ``i`` in the | |
| | | range |begin/end<v>| and each ``j`` in for in the range | |
| | transform_view<s,f> | |begin/end<s>| ``deref<i>::type`` is identical to | |
| | transform_view<s,f>::type | ``apply< f, deref<j>::type >::type``. | |
| +-----------------------------------+-----------------------------------------------------------+ |
| | ``size<v>::type`` | The size of ``v``; | |
| | | ``size<v>::value == size<s>::value``; | |
| | | linear complexity; see |Forward Sequence|. | |
| +-----------------------------------+-----------------------------------------------------------+ |
| |
| |
| Example |
| ------- |
| |
| Find the largest type in a sequence. |
| |
| .. parsed-literal:: |
| |
| typedef vector<int,long,char,char[50],double> types; |
| typedef max_element< |
| transform_view< types, size_of<_> > |
| >::type iter; |
| |
| BOOST_MPL_ASSERT_RELATION( deref<iter>::type::value, ==, 50 ); |
| |
| |
| See also |
| -------- |
| |
| |Sequences|, |Views|, |filter_view|, |joint_view|, |zip_view|, |iterator_range| |
| |
| |
| .. 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) |
