.. _py-rule/GraphInterface:

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rule/GraphInterface
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.. default-domain:: py

.. py:currentmodule:: mod
.. cpp:namespace:: mod

.. class:: Rule.LeftGraph

    A proxy object representing the left graph of the rule.
    The class implements the :class:`protocols.LabelledGraph` protocol,

    .. attribute:: rule

        (Read-only) The rule the graph belongs to.

        :type: Rule
    .. class:: Vertex

        A descriptor of either a vertex in a left side, or a null vertex.
        Implements the :class:`protocols.LabelledGraph.Vertex` protocol.
        Additionally, the :attr:`id <protocols.Graph.Vertex.id>` is in the range :math:`[0, numCoreVertices[`.

        .. attribute:: core

            (Read-only) The descriptor for this vertex in the core graph.

            :type: Rule.Vertex
        .. attribute:: rule

            (Read-only) The rule the vertex belongs to.

            :type: Rule
            :raises: :class:`LogicError` if it is a null descriptor.
    .. class:: Edge

        A descriptor of either an edge in a left side, or a null edge.
        Implements the :class:`protocols.LabelledGraph.Edge` protocol.

        .. attribute:: core

            (Read-only) The descriptor for this edge in the core graph.

            :type: Rule.Edge
        .. attribute:: rule

            (Read-only) The rule the edge belongs to.

            :type: Rule
            :raises: :class:`LogicError` if it is a null descriptor.
    .. class:: VertexRange

        Implements the :class:`protocols.Graph.VertexRange` protocol.

    .. class:: EdgeRange

        Implements the :class:`protocols.Graph.EdgeRange` protocol.

    .. class:: IncidentEdgeRange

        Implements the :class:`protocols.Graph.IncidentEdgeRange` protocol.

.. class:: Rule.ContextGraph

    A proxy object representing the context graph of the rule.
    The class implements the :class:`protocols.Graph` protocol,

    .. attribute:: rule

        (Read-only) The rule the graph belongs to.

        :type: Rule
    .. class:: Vertex

        A descriptor of either a vertex in a context, or a null vertex.
        Implements the :class:`protocols.Graph.Vertex` protocol.
        Additionally, the :attr:`id <protocols.Graph.Vertex.id>` is in the range :math:`[0, numCoreVertices[`.

        .. attribute:: core

            (Read-only) The descriptor for this vertex in the core graph.

            :type: Rule.Vertex
        .. attribute:: rule

            (Read-only) The rule the vertex belongs to.

            :type: Rule
            :raises: :class:`LogicError` if it is a null descriptor.
    .. class:: Edge

        A descriptor of either an edge in a context, or a null edge.
        Implements the :class:`protocols.LabelledGraph.Edge` protocol.

        .. attribute:: core

            (Read-only) The descriptor for this edge in the core graph.

            :type: Rule.Edge
        .. attribute:: graph

            (Read-only) The rule the edge belongs to.

            :type: Rule
            :raises: :class:`LogicError` if it is a null descriptor.
    .. class:: VertexRange

        Implements the :class:`protocols.Graph.VertexRange` protocol.

    .. class:: EdgeRange

        Implements the :class:`protocols.Graph.EdgeRange` protocol.

    .. class:: IncidentEdgeRange

        Implements the :class:`protocols.Graph.IncidentEdgeRange` protocol.

.. class:: Rule.RightGraph

    A proxy object representing the right graph of the rule.
    The class implements the :class:`protocols.LabelledGraph` protocol,

    .. attribute:: rule

        (Read-only) The rule the graph belongs to.

        :type: Rule
    .. class:: Vertex

        A descriptor of either a vertex in a right side, or a null vertex.
        Implements the :class:`protocols.LabelledGraph.Vertex` protocol.
        Additionally, the :attr:`id <protocols.Graph.Vertex.id>` is in the range :math:`[0, numCoreVertices[`.

        .. attribute:: core

            (Read-only) The descriptor for this vertex in the core graph.

            :type: Rule.Vertex
        .. attribute:: rule

            (Read-only) The rule the vertex belongs to.

            :type: Rule
            :raises: :class:`LogicError` if it is a null descriptor.
    .. class:: Edge

        A descriptor of either an edge in a right side, or a null edge.
        Implements the :class:`protocols.LabelledGraph.Edge` protocol.

        .. attribute:: core

            (Read-only) The descriptor for this edge in the core graph.

            :type: Rule.Edge
        .. attribute:: rule

            (Read-only) The rule the edge belongs to.

            :type: Rule
            :raises: :class:`LogicError` if it is a null descriptor.
    .. class:: VertexRange

        Implements the :class:`protocols.Graph.VertexRange` protocol.

    .. class:: EdgeRange

        Implements the :class:`protocols.Graph.EdgeRange` protocol.

    .. class:: IncidentEdgeRange

        Implements the :class:`protocols.Graph.IncidentEdgeRange` protocol.

.. class:: Rule.Vertex

    Implements the :class:`protocols.Graph.Vertex` protocol.
    Additionally, the :attr:`id <protocols.Graph.Vertex.id>` is in the range :math:`[0, numVertices[`.

    .. attribute:: rule

        An alias for :attr:`protocols.Graph.Vertex.graph`.

        :type: Rule
    .. attribute:: left

        (Read-only) A null descriptor if this vertex is not in the left graph,
        otherwise the descriptor of this vertex in the left graph.

        :type: LeftGraph.Vertex
    .. attribute:: context

        (Read-only) A null descriptor if this vertex is not in the context graph,
        otherwise the descriptor of this vertex in the context graph.

        :type: ContextGraph.Vertex
    .. attribute:: right

        (Read-only) A null descriptor if this vertex is not in the right graph,
        otherwise the descriptor of this vertex in the right graph.

        :type: RightGraph.Vertex
    .. method:: get2DX(withHydrogens=True)

        :returns: the x-coordinate in a 2D depiction of the rule.
            Different sets of coordinates exists for rendering with and without certain hydrogens.
        :rtype: float
        :raises: :class:`LogicError` if it is a null descriptor, or
            if ``withHydrogens`` is ``True`` and the vertex is a "clean" hydrogen.
    .. method:: get2DY(withHydrogens=True)

        :returns: the y-coordinate in a 2D depiction of the rule.
            Different sets of coordinates exists for rendering with and without certain hydrogens.
        :rtype: float
        :raises: :class:`LogicError` if it is a null descriptor, or
            if ``withHydrogens`` is ``True`` and the vertex is a "clean" hydrogen.
.. class:: Rule.Edge

    Implements the :class:`protocols.Graph.Edge` protocol.

    .. attribute:: rule

        An alias for :attr:`protocols.Graph.Edge.graph`.

        :type: Rule
    .. attribute:: left

        (Read-only) A null descriptor if this edge is not in the left graph,
        otherwise the descriptor of this edge in the left graph.

        :type: LeftGraph.Edge
    .. attribute:: context

        (Read-only) A null descriptor if this edge is not in the context graph,
        otherwise the descriptor of this edge in the context graph.

        :type: ContextGraph.Edge
    .. attribute:: right

        (Read-only) A null descriptor if this edge is not in the right graph,
        otherwise the descriptor of this edge in the right graph.

        :type: RightGraph.Edge
.. class:: Rule.VertexRange

    Implements the :class:`protocols.Graph.VertexRange` protocol,
    in addition to the following functionality.

    .. method:: __getitem__(i)

        :returns: the ``i``\ th vertex of the graph.
        :rtype: Rule.Vertex
.. class:: Rule.EdgeRange

    Implements the :class:`protocols.Graph.EdgeRange` protocol.

.. class:: Rule.IncidentEdgeRange

    Implements the :class:`protocols.Graph.IncidentEdgeRange` protocol.