/// <summary>
/// Register a state for the given <paramref name="sateTag"/>. The new state doesn't contain any
/// edges.
/// </summary>
/// <param name="fromStateTag">The tag of the state from which the edge originates.</param>
/// <param name="edgeTag">The tag of the edge that is registered.</param>
/// <param name="toStateTag">The tag of the state to which the edge maps.</param>
/// <returns>A <see cref="T:IEdge`2"/> instance that is either an already registered
/// state with the given <paramref name="stateTag"/> or a new state created.</returns>
/// <remarks>
/// <para>If there is no state associated with the <paramref name="fromStateTag"/> or <paramref name="toStateTag"/>,
/// states are registered (using the <see cref="M:RegisterState"/> method) for these tags.</para>
/// <para>If there already exists an edge between the two given states with the given tag, no additional
/// edge is registered.</para>
/// <para>This operation is not completely specific to the given automaton: if the state is shared with another
/// automaton, the edge will be added to all the automata.</para>
/// </remarks>
public IEdge <TStateTag, TEdgeTag> RegisterEdge(TStateTag fromStateTag, TEdgeTag edgeTag, TStateTag toStateTag)
{
IState <TStateTag, TEdgeTag> frm = this.RegisterState(fromStateTag);
IState <TStateTag, TEdgeTag> tos = this.RegisterState(toStateTag);
foreach (IEdge <TStateTag, TEdgeTag> edge in frm.TaggedEdges(edgeTag))
{
if (edge.Contains(tos))
{
return(edge);
}
}
Edge <TStateTag, TEdgeTag> cedge = new Edge <TStateTag, TEdgeTag> (edgeTag, tos);
frm.AddEdge(cedge);
return(cedge);
}
