regina::ChildIterator< const_ > Class Template Reference

A forward iterator for iterating through all immediate children of a given packet. More...

#include <packet/packet.h>

Public Types
using	value_type = std::conditional_t< const_, const Packet, Packet >
	Indicates what the iterator points to. More...
using	iterator_category = std::forward_iterator_tag
	Declares this to be a forward iterator type. More...
using	difference_type = ptrdiff_t
	The type obtained by subtracting iterators. More...
using	pointer = value_type *
	A pointer to value_type. More...
using	reference = value_type &
	A reference to value_type. More...

Public Member Functions
	ChildIterator ()=default
	Creates a past-the-end iterator. More...
	ChildIterator (const ChildIterator &)=default
	Creates a new copy of the given iterator. More...
	ChildIterator (std::shared_ptr< value_type > current)
	Creates a new iterator pointing to the given child packet. More...
ChildIterator &	operator= (const ChildIterator &)=default
	Sets this to be a copy of the given iterator. More...
bool	operator== (const ChildIterator &rhs) const
	Tests whether this and the given iterator are equal. More...
bool	operator!= (const ChildIterator &rhs) const
	Tests whether this and the given iterator are different. More...
ChildIterator &	operator++ ()
	Preincrement operator. More...
ChildIterator	operator++ (int)
	Postincrement operator. More...
auto	__next__ ()
	Returns the current child packet and increments this iterator. More...
value_type &	operator* () const
	Returns the packet that this iterator is currently pointing to. More...
	operator bool () const
	Identifies whether this iterator is dereferencable. More...

Detailed Description

template<bool const_>
class regina::ChildIterator< const_ >

A forward iterator for iterating through all immediate children of a given packet.

Each iterator will hold a std::shared_ptr to the packet whose children it is iterating over. This guarantees that the packet will not be destroyed mid-iteration, but it also means that you must ensure that you dispose of your iterators once you are finished with them.

Template Parameters

const_

Indicates whether this iterator should offer const or non-const access to the child packets.

Python

Instead of the C++ interface described here, in Python the classes PacketChildren and ChildIterator together implement the Python iterable/iterator interface. The class PacketChildren has just the single function __iter__(), which returns a ChildIterator; then ChildIterator implements __next__(), which either returns the next child packet in the iteration or else throws a StopException if there are no more children to return. All iteration in Python is non-const (i.e., Python exclusively uses the classes where const_ is false).

Member Typedef Documentation

difference_type

template<bool const_>

using regina::ChildIterator< const_ >::difference_type = ptrdiff_t

The type obtained by subtracting iterators.

iterator_category

template<bool const_>

using regina::ChildIterator< const_ >::iterator_category = std::forward_iterator_tag

Declares this to be a forward iterator type.

pointer

template<bool const_>

using regina::ChildIterator< const_ >::pointer = value_type*

A pointer to value_type.

reference

template<bool const_>

using regina::ChildIterator< const_ >::reference = value_type&

A reference to value_type.

value_type

template<bool const_>

using regina::ChildIterator< const_ >::value_type = std::conditional_t<const_, const Packet, Packet>

Indicates what the iterator points to.

This is either Packet or const Packet, according to the template argument const_.

Constructor & Destructor Documentation

ChildIterator() [1/3]

template<bool const_>

regina::ChildIterator< const_ >::ChildIterator ( )

default

Creates a past-the-end iterator.

Python

Not present. The only way to create a ChildIterator is via Packet::children().

ChildIterator() [2/3]

template<bool const_>

regina::ChildIterator< const_ >::ChildIterator ( const ChildIterator< const_ > &  )

default

Creates a new copy of the given iterator.

Python

Not present. The only way to create a ChildIterator is via Packet::children().

ChildIterator() [3/3]

template<bool const_>

regina::ChildIterator< const_ >::ChildIterator ( std::shared_ptr< value_type >  current )

inline

Creates a new iterator pointing to the given child packet.

Python

Not present. The only way to create a ChildIterator is via Packet::children().

Parameters

current

the child packet that the new iterator should point to, or null if the new iterator should be past-the-end.

Member Function Documentation

__next__()

template<bool const_>

auto regina::ChildIterator< const_ >::__next__

(

)

Returns the current child packet and increments this iterator.

C++

Not present. For C++ users, ChildIterator provides the usual iterator preincrement, postincrement and dereferencing operators (++ and *) instead.

Exceptions

StopIteration

The iterator is already past-the-end when this function is called.

Returns

the child packet that this iterator is pointing to, before the increment takes place.

operator bool()

template<bool const_>

regina::ChildIterator< const_ >::operator bool

inline

Identifies whether this iterator is dereferencable.

Python

Not present. For Python users, ChildIterator implements the Python iterator interface instead. See next() for details.

Returns

true if and only if this is dereferencable (i.e., not past-the-end).

operator!=()

template<bool const_>

bool regina::ChildIterator< const_ >::operator!= ( const ChildIterator< const_ > &  rhs ) const

inline

Tests whether this and the given iterator are different.

Returns

true if and only if the two iterators are different.

operator*()

template<bool const_>

ChildIterator< const_ >::value_type & regina::ChildIterator< const_ >::operator*

inline

Returns the packet that this iterator is currently pointing to.

Precondition

This iterator is dereferenceable (i.e., it is not past-the-end).

Python

Not present. For Python users, ChildIterator implements the Python iterator interface instead. See next() for details.

Returns

the current packet.

operator++() [1/2]

template<bool const_>

ChildIterator< const_ > & regina::ChildIterator< const_ >::operator++

inline

Preincrement operator.

Precondition

This iterator is dereferenceable (i.e., it is not past-the-end).

Python

Not present. For Python users, ChildIterator implements the Python iterator interface instead. See next() for details.

Returns

a reference to this iterator.

operator++() [2/2]

template<bool const_>

ChildIterator< const_ > regina::ChildIterator< const_ >::operator++ ( int  )

inline

Postincrement operator.

Precondition

This iterator is dereferenceable (i.e., it is not past-the-end).

Python

Not present. For Python users, ChildIterator implements the Python iterator interface instead. See next() for details.

Returns

a a copy of this iterator before it was incremented.

operator=()

template<bool const_>

ChildIterator & regina::ChildIterator< const_ >::operator= ( const ChildIterator< const_ > &  )

default

Sets this to be a copy of the given iterator.

Returns

a reference to this iterator.

operator==()

template<bool const_>

bool regina::ChildIterator< const_ >::operator== ( const ChildIterator< const_ > &  rhs ) const

inline

Tests whether this and the given iterator are equal.

Returns

true if and only if the two iterators are equal.

---

The documentation for this class was generated from the following file:

• packet/packet.h