bool IMutableVertexAndEdgeSet <TVertex, TEdge> .AddVerticesAndEdge(TEdge edge)
{
IMutableVertexAndEdgeSet <TVertex, TEdge> ithis = this;
Contract.Requires(edge != null);
Contract.Ensures(ithis.ContainsEdge(edge));
Contract.Ensures(ithis.AllowParallelEdges || Contract.Result <bool>() == Contract.OldValue(!ithis.ContainsEdge(edge)));
Contract.Ensures(ithis.EdgeCount == Contract.OldValue(ithis.EdgeCount) + (Contract.Result <bool>() ? 1 : 0));
return(default(bool));
}
bool IMutableVertexAndEdgeSet <TVertex, TEdge> .AddVerticesAndEdge(TEdge edge)
{
IMutableVertexAndEdgeSet <TVertex, TEdge> ithis = this;
Contract.Requires(edge != null);
Contract.Ensures(ithis.ContainsEdge(edge));
// MJ: This doesn't work, because the check for ContainsEdge bugs out
// Contract.Ensures(ithis.AllowParallelEdges || Contract.Result<bool>() == Contract.OldValue(!ithis.ContainsVertex(edge.Source) || !ithis.ContainsEdge(edge)));
Contract.Ensures(ithis.EdgeCount == Contract.OldValue(ithis.EdgeCount) + (Contract.Result <bool>() ? 1 : 0));
return(default(bool));
}