transform_view

Synopsis

template<
      typename Sequence
    , typename F
    >
struct transform_view
{
    // unspecified
    // ...
};

Description

A view the full range of Sequence's transformed elements.

Header

#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

The semantics of an expression are defined only where they differ from, or are not defined in 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
transform_view<s,f> transform_view<s,f>::type	A lazy Forward Sequence such that for each `i` in the range [`begin<v>::type`, `end<v>::type`) and each `j` in for in the range [`begin<s>::type`, `end<s>::type`) `deref<i>::type` is identical to `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.

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 );