print("subgraph cluster_" + getName() + " {\n");
print("subgraph cluster_" + getName() + " {\n label=\"" + self.getIdent() + "\";\n");
    public Object visitPipeline(SIRPipeline self,                                JFieldDeclaration[] fields,                                JMethodDeclaration[] methods,                                JMethodDeclaration init)    {        NamePair pair = new NamePair();                // Print this within a subgraph.        print("subgraph cluster_" + getName() + " {\n");                // Walk through each of the elements in the pipeline.        Iterator iter = self.getChildren().iterator();        while (iter.hasNext())        {            SIROperator oper = (SIROperator)iter.next();            NamePair p2 = (NamePair)oper.accept(this);            printEdge(pair.last, p2.first);            // Update the known edges.            if (pair.first == null)                pair.first = p2.first;            pair.last = p2.last;        }        print("}\n");        return pair;    }