identity_view

Description

identity_view presents underlying sequence unchanged.

Header

#include <boost/fusion/view/identity_view.hpp>
#include <boost/fusion/include/identity_view.hpp>

Synopsis

template <typename Sequence>
struct identity_view;

Template parameters

Parameter	Description	Default
`Sequence`	A Forward Sequence

Model of

A model of Forward Sequence if Sequence is a Forward Sequence else, Bidirectional Sequence if Sequence is a Bidirectional Sequence else, Random Access Sequence if Sequence is a Random Access Sequence.
Associative Sequence if Sequence implements the Associative Sequence model.

Notation

IV: An identity_view type
s: An instance of Sequence
iv, iv2: Instances of identity_view

Expression Semantics

Semantics of an expression is defined only where it differs from, or is not defined in the implemented models.

Expression	Semantics
`IV(s)`	Creates an `identity_view` given sequence, `s`.
`IV(iv)`	Copy constructs an `identity_view` from another `identity_view`, `iv`.
`iv = iv2`	Assigns to an `identity_view`, `iv`, from another `identity_view`, `iv2`.

Example

typedef vector<int, short, double> vector_type;
vector_type vec(2, 5, 3.3);

identity_view<vector_type> identity(vec);
std::cout << identity << std::endl; // (2 5 3.3)