Elements
========

.. toctree::
   :maxdepth: 0
   :hidden:

:cpp:include:`#include<hysj/graphs/elements.hpp>`

.. cpp:namespace:: hysj

.. cpp:namespace-push:: graphs

In namespace :cpp:any:`graphs`:

.. cpp:enum-class:: element_tag

   .. rest-script::

      from hysj.graphs import ElementTag as Enum

      for e in Enum.__members__.values():
        print(f'.. cpp:enumerator:: {e.name}')

   | Names the elements of a graph, vertices and edges.
   |

.. cpp:function:: auto direction(const auto &graph,auto id)

   | Hook for computing the direction of an edge.
   |

.. cpp:function:: auto element_ids(auto element_tag,const auto &graph)

   | Hook for computing the element ids of a graph.
   |

*Shorthands*

.. rest-script::

   from hysj.graphs import ElementTag as Enum

   for e in Enum.__members__.values():
     print(f'.. cpp:var:: unspecified {e.name}_ids = bind(element_ids,{e.name}_tag)')

|

.. cpp:function:: auto element_count(auto element_tag,const auto &graph)

   | Hook for computing the number of elements in a graph.
   |
   
*Shorthands*

.. cpp:var:: unspecified order = bind(element_count,in_tag)
	     unspecified size = bind(element_count,out_tag)

   |

.. cpp:function:: auto swap(auto element_tag,const auto &graph,auto id0,auto id1)

   | Hook for swapping the relations of elements :cpp:var:`id0` and :cpp:var:`id1`.
   |


.. cpp:struct:: template<typename G,element_tag T> traits::element_id_trait
.. cpp:type:: template<typename G,element_tag T> traits::element_id 

   | Trait for computing the id-type of a given element-type.
   |

.. cpp:concept:: template<typename G,element_tag T> concepts::elements

   | Whether :cpp:type:`G` is a container of elements of tag :cpp:expr:`T`.

   *Let*
     .. cpp:var:: G g

   *Requires*
     :cpp:expr:`typename traits::element_id<G,T>`
     :cpp:expr:`graphs::element_ids(constant_t<T>{},g)`
     :cpp:expr:`graphs::element_count(constant_t<T>{},g)`

Builtin
^^^^^^^

.. cpp:namespace-push:: builtin

:cpp:include:`#include<hysj/graphs/builtin/element_ids.hpp>`

In namespace :cpp:any:`builtin`:

.. cpp:struct:: template<element_tag T> basic_element_id

   .. cpp:member:: static constexpr auto tag = constant_c<T>
   .. cpp:member:: natural value

   | Implements a basic element id.
   |

*Shorthands*

.. rest-script::

   from hysj.graphs import ElementTag as Enum

   for e in Enum.__members__.values():
     print(f'.. cpp:type:: {e.name}_id = basic_element_id<element_tag::{e.name}>')

|

.. cpp:struct:: dynamically_directed_edge_id

   .. cpp:member:: edge_id id
   .. cpp:member:: direction_tag direction

   |

.. cpp:struct:: template<direction_tag direction> statically_directed_edge_id

   .. cpp:member:: edge_id id

   |

.. cpp:namespace-pop::

.. cpp:namespace-pop::