View Template Library

polymorphic_view<Container, Const_tag, Base>


Category: adaptors	Component type: type

Description

The polymorphic_view is a tranform_view where the container objects are pointers, and the transformation is dereference. The properties of any polymorphic_view instance depend on the properties of the container template parameter. The interface of polymorphic_view adapts itself [1] to the referenced container, if this is one of Container, Forward Container, Reversible Container, Random Access Container, Sequence.

The polymorphic_view presents transformed values, by applying the operator*() transformation to the contents of the iterators. Transformation is only applied in presenting the elements, the container's elements themselves are not altered.

The properties of the order of elements are the same as those provided by the underlying container, as is the validity of more than one active iterators at any one time.

A polymorphic_view owns its referenced container, if its base template parameter is aggregated_ownership, it merely references its container, if the base template parameter is referenced_ownership.

Template parameters

Parameter	Description	Default
`container`	The view's container type: the type of container referenced by this view
`const_tag`	The view's const tag: either `const_view_tag` or `mutable_view_tag`	`const_view_tag`
`base`	The view's ownership type: the base class that determines if the view references or owns the container	`referenced_ownership`

Definition

Defined in the header polymorphic_view.hpp.

Model of

View

Type requirements

Container::value_type must have a operator*().

Members

Member	Where defined	Description
`value_type`	Container	The type *`T` of the elements accessed through the container.
`domain_t`	view	The type of the referenced container.
`pointer`	Container	Pointer to `T`.
`reference`	Container	`T`
`const_reference`	Container	`const T`
`size_type`	Container	An unsigned integral type.
`difference_type`	Container	A signed integral type.
`iterator`	Container	Iterator used to iterate through the view.
`const_iterator`	Container	Const iterator used to iterate through the view.
`reverse_iterator`	Reversible Container	Iterator used to iterate backwards through a container.
`const_reverse_iterator`	Reversible Container	Const iterator used to iterate backwards through a container.
`iterator begin()`	Container	Returns an iterator pointing to the begin of the view.
`iterator end()`	Container	Returns an iterator pointing to the end of the view.
`const_iterator begin() const`	Container	Returns a const_iterator pointing to the begin of the view.
`const_iterator end() const`	Container	Returns a const_iterator pointing to the end of the view.
`reverse_iterator rbegin()`	Reversible Container	Valid for reversible container's only. Returns a `reverse_iterator` pointing to the beginning of the reversed container.
`reverse_iterator rend()`	Reversible Container	Valid for reversible container's only. Returns a `reverse_iterator` pointing to the end of the reversed container.
`const_reverse_iterator rbegin() const`	Reversible Container	Valid for reversible container's only. Returns a `const_reverse_iterator` pointing to the beginning of the reversed container.
`const_reverse_iterator rend() const`	Reversible Container	Valid for reversible container's only. Returns a `const_reverse_iterator` pointing to the end of the reversed container.
`reference front()`	Sequence	Returns a `reference` for the first element in the `container`. Only supported if container is a sequence.
`reference back()`	Sequence	Returns a `reference` for the last element in the `container`. Only supported if container is a sequence.
`const_reference front() const`	Sequence	Returns a `const_reference` for the first element in the `container`. Only supported if container is a sequence.
`const_reference back() const`	Sequence	Returns a `const_reference` for the last element in the `container`. Only supported if container is a sequence.
`void pop_front()`	Sequence	Call pop_front on the underlying container.
`void pop_back()`	Sequence	Call pop_back on the underlying container.
`reference operator[](size_type n)`	Random access container	Returns a `reference` for the nth element in the `container`. Only supported if container is random access.
`const_reference operator[](size_type n) const`	Random access container	Returns a `const_reference` for the nth element in the `container`. Only supported if container is random access.
`reference at(size_type n)`	Random access container	Returns a `reference` for the nth element in the `container`. Only supported if container is random access. Does a range check on n and will throw `std::range_error` if it fails.
`const_reference at(size_type n) const`	Random access container	Returns a `const_reference` for the nth element in the `container`. Only supported if container is random access. Does a range check on n and will throw `std::range_error` if it fails.
`size_type size() const`	Container	Returns the size of the view.
`size_type max_size() const`	Container	Returns the largest possible size of the view.
`bool empty() const`	Container	true if the view's size is 0.
`polymorphic_view()`	view	Creates an empty view.
`polymorphic_view(container_t&)`	view	Creates a view of given container.
`void swap(polymorphic_view&)`	Container	Swaps the two views. Iterators are invalidated by this operation. For referencing views, the containers themselves are not swapped.
`bool operator==(const polymorphic_view&, const polymorphic_view&)`	Forward Container	Tests two views for equality. This is a global function, not a member function. Views may be equal even if their referenced containers are not.
`bool operator<(const polymorphic_view&, const polymorphic_view&)`	Forward Container	Lexicographical comparison. This is a global function, not a member function.