flatten_view

Description

flatten_view presents a view which iterates over its elements recursively in depth-first order.

Header

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

Synopsis

template <typename Sequence>
struct flatten_view;

Template parameters

Parameter	Description	Default
`Sequence`	A Forward Sequence

Model of

Forward Sequence

Notation

F: A flatten_view type
s: An instance of Sequence
f, f2: Instances of F

Expression Semantics

Semantics of an expression is defined only where it differs from, or is not defined in Forward Sequence.

Expression	Semantics
`F(s)`	Creates a `flatten_view` given sequence, `s`.
`F(f)`	Copy constructs a `flatten_view` from another `flatten_view`, `f`.
`f = f2`	Assigns to a `flatten_view`, `f`, from another `flatten_view`, `f2`.

Example

typedef vector<int, int, vector<int, int>, int> sequence_type;
sequence_type seq;
flatten_view<sequence_type> flattened(seq);
copy(make_vector(1, 2, 3, 4, 5), flattened);
assert(seq == make_vector(1, 2, make_vector(3, 4), 5));