Subgraphs

[moaxcp]

• Define components of graph

graph {
    edge 'A', 'B'  
    subgraph {
        edge 'C', 'D'
        subgraph {
            edge 'X', 'Y'
        }
    }
    edge 'Y', 'Z'
}

• When a vertex or edge is added it is added to parent subgraphs and main graph (may need listeners)
• graphs are maps
• subgraph is a graph
• subgraph can have subgraphs
• if vertex or edge is missing an entry it will check all parent graphs for entry and return found value
• vertex or edge can be in multiple subgraphs
• subgraph is always same type as main graph (share type variable)
• subgraphs can be
• if a named subgraph is used inside other subgraphs what is the behavior. How does grapgviz do it?

Graph {
    subgraph {
        color = 'blue'
        edge 'A', 'B'
    }
}

Edge and vertices will be blue.

[moaxcp]

In graphviz

If a default attribute is defined using a node, edge, or graph statement, or by an attribute assignment not attached to a node or edge, any object of the appropriate type defined afterwards will inherit this attribute value. This holds until the default attribute is set to a new value, from which point the new value is used. Objects defined before a default attribute is set will have an empty string value attached to the attribute once the default attribute definition is made.