The MPL Reference Manual: transform_view

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 transform_view::type	A lazy Forward Sequence such that for each `i` in the range [`begin::type`, `end::type`) and each `j` in for in the range [`begin::type`, `end::type`) `deref::type` is identical to `apply< f, deref::type >::type`.
`size::type`	The size of `v`; `size::value == size::value`~~; linear complexity; see Forward Sequence.~~

Example

Find the largest type in a sequence.

typedef vector types;
typedef max_element<
      transform_view< types, size_of<_> >
    >::type iter;

BOOST_MPL_ASSERT_RELATION( deref::type::value, ==, 50 );

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