Child Extraction

Collaboration diagram for Child Extraction:

Typedefs
template<typename Node, std::size_t... indices>
using	Dune::TypeTree::Child = typename Impl::ChildTraits<Node, indices...>::type
	Template alias for the type of a child node given by a list of child indices.
template<typename Node, typename TreePath>
using	Dune::TypeTree::ChildForTreePath = std::decay_t<decltype(child(std::declval<Node>(), std::declval<TreePath>()))>
	Template alias for the type of a child node given by a TreePath type.

Functions
template<typename Node, typename... Indices>
decltype(auto)	Dune::TypeTree::child (Node &&node, TreePath< Indices... > treePath)
	Extracts the child of a node given by a TreePath object.
template<typename Node, typename... Indices>
decltype(auto)	Dune::TypeTree::child (Node &&node, Indices... indices)
	Extracts the child of a node given by a sequence of compile-time and run-time indices.

Detailed Description

Utility functions and metafunctions for extracting children from a TypeTree.

Typedef Documentation

Child

template<typename Node, std::size_t... indices>

using Dune::TypeTree::Child = typename Impl::ChildTraits<Node, indices...>::type

Template alias for the type of a child node given by a list of child indices.

This template alias is implemented in terms of the free-standing child() functions and uses those in combination with decltype() to extract the child type.

Template Parameters

Node	The type of the parent node.
indices	A list of index values the describes the path to the wanted child.

ChildForTreePath

template<typename Node, typename TreePath>

using Dune::TypeTree::ChildForTreePath = std::decay_t<decltype(child(std::declval<Node>(), std::declval<TreePath>()))>

Template alias for the type of a child node given by a TreePath type.

This template alias is implemented in terms of the free-standing child() functions and uses those in combination with decltype() to extract the child type.

Template Parameters

Node	The type of the parent node.
TreePath	The type of a TreePath that describes the path to the wanted child.

Function Documentation

child() [1/2]

template<typename Node, typename... Indices>

decltype(auto) Dune::TypeTree::child	(	Node &&	node,
		Indices...	indices )

Extracts the child of a node given by a sequence of compile-time and run-time indices.

Use this function to extract a (possibly indirect) child of a TypeTree node.

Example:

using namespace Dune::Indices;   // for compile-time indices
auto&& c = child(node,_4,2,_0,1);

returns the second child of the first child of the third child of the fifth child of node, where some child lookups were done using a compile-time index and some using a run-time index.

Parameters

node	The node from which to extract the child.
indices	A list of indices that describes the path into the tree to the wanted child. These parameters can be a combination of run time indices (for tree nodes that allow accessing their children using run time information, like PowerNode) and instances of index_constant, which work for all types of inner nodes.

Returns

A reference to the child, its cv-qualification depends on the passed-in node.

child() [2/2]

template<typename Node, typename... Indices>

decltype(auto) Dune::TypeTree::child	(	Node &&	node,
		TreePath< Indices... >	treePath )

Extracts the child of a node given by a TreePath object.

Use this function to extract a (possibly indirect) child of a TypeTree node.

Example:

using namespace Dune::Indices; // for compile-time indices
auto tp = Dune::TypeTree::TreePath(_4,2,_0,1);
auto&& c = child(node,tp);

returns the second child of the first child of the third child of the fifth child of node, where some child lookups were done using a compile-time index and some using a run-time index.

Parameters

node	The node from which to extract the child.
treePath	A TreePath that describes the path into the tree to the wanted child. This tree path object can be a combination of run time indices (for tree nodes that allow accessing their children using run time information, like PowerNode) and instances of index_constant, which work for all types of inner nodes.

Returns

A reference to the child, its cv-qualification depends on the passed-in node.