regina::PacketChildren< const_ > Class Template Reference

A lightweight object that gives access to all immediate children of a given packet. More...

#include <packet/packet.h>

Public Types
using	packet_type = std::conditional_t< const_, const Packet, Packet >
	Either Packet or const Packet, according to the template argument const_. More...

Public Member Functions
	PacketChildren (const PacketChildren &)=default
	Creates a new object for iterating through the children of the same packet as the given object. More...
	PacketChildren (std::shared_ptr< packet_type > parent)
	Creates a new object for iterating through the immediate children of the given packet. More...
PacketChildren &	operator= (const PacketChildren &)=default
	Sets this object to iterate over the children of the same packet as the given object. More...
ChildIterator< const_ >	begin () const
	Returns a C++ iterator pointing to the first immediate child packet. More...
ChildIterator< const_ >	end () const
	Returns a C++ iterator pointing beyond the last immediate child packet. More...
auto	__iter__ () const
	Returns a Python iterator over all immediate child packets. More...
bool	operator== (const PacketChildren &rhs) const
	Determines whether this and the given object are designed to iterate over children of the same parent packet. More...
bool	operator!= (const PacketChildren &rhs) const
	Determines whether this and the given object are designed to iterate over children of different parent packets. More...

Detailed Description

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

A lightweight object that gives access to all immediate children of a given packet.

The purpose of this class is to support iteration through all children of a packet p using range-based for loops:

std::shared_ptr<Packet> parent = ...;
for (Packet& child : parent->children()) { ... }

In Python, PacketChildren is an iterable object:

parent = ...
for child in parent.children():
    ...

Each object of this class will hold a std::shared_ptr to the packet whose children it gives access to. This guarantees that the packet will not be destroyed during iteration, but it also means that you must ensure that you dispose of these objects once you are finished with them.

These are lightweight objects, small enough to pass by value and swap with std::swap(), with no need for any specialised move operations or swap functions. Copies of a PacketChildren will iterate over the children of the same underlying packet.

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

packet_type

template<bool const_>

using regina::PacketChildren< const_ >::packet_type = std::conditional_t<const_, const Packet, Packet>

Either Packet or const Packet, according to the template argument const_.

Constructor & Destructor Documentation

PacketChildren() [1/2]

template<bool const_>

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

default

Creates a new object for iterating through the children of the same packet as the given object.

Python

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

PacketChildren() [2/2]

template<bool const_>

regina::PacketChildren< const_ >::PacketChildren ( std::shared_ptr< packet_type >  parent )

inline

Creates a new object for iterating through the immediate children of the given packet.

Python

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

Parameters

parent

the packet whose children we will iterate through.

Member Function Documentation

__iter__()

template<bool const_>

auto regina::PacketChildren< const_ >::__iter__

(

)

const

Returns a Python iterator over all immediate child packets.

C++

Not present. For C++ users, PacketChildren provides the usual begin() and end() functions instead. In particular, this allows you to iterate through all immediate child packets in the usual way using a range-based for loop.

Returns

an iterator over all immediate child packets.

begin()

template<bool const_>

ChildIterator< const_ > regina::PacketChildren< const_ >::begin

inline

Returns a C++ iterator pointing to the first immediate child packet.

The iterator range from begin() to end() runs through all immediate children in order from first to last.

Python

Not present. For Python users, PacketChildren implements the Python iterable interface. You can iterate over all immediate child packets in the usual Python way, by treating this PacketChildren object as you would any native Python container.

Returns

the beginning iterator.

end()

template<bool const_>

ChildIterator< const_ > regina::PacketChildren< const_ >::end

inline

Returns a C++ iterator pointing beyond the last immediate child packet.

The iterator range from begin() to end() runs through all immediate children in order from first to last.

Python

Not present. For Python users, PacketChildren implements the Python iterable interface. You can iterate over all immediate child packets in the usual Python way, by treating this PacketChildren object as you would any native Python container.

Returns

the past-the-end iterator.

operator!=()

template<bool const_>

bool regina::PacketChildren< const_ >::operator!=

(

const PacketChildren< const_ > &

rhs

)

const

Determines whether this and the given object are designed to iterate over children of different parent packets.

Returns

true if and only if this object and rhs iterate over children of different packets.

operator=()

template<bool const_>

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

default

Sets this object to iterate over the children of the same packet as the given object.

Returns

a reference to this object.

operator==()

template<bool const_>

bool regina::PacketChildren< const_ >::operator==

(

const PacketChildren< const_ > &

rhs

)

const

Determines whether this and the given object are designed to iterate over children of the same parent packet.

Returns

true if and only if this object and rhs iterate over children of the same packet.

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

• packet/packet.h