Not sure if our friends in Windows and Mac land would find this possible but having:
[source,graphviz]
-----
digraph G {
main -> parse -> execute;
main -> init;
main -> cleanup;
execute -> make_string;
execute -> printf
init -> make_string;
main -> printf;
execute -> compare;
}
-----
and then it render a graphviz graph in web or pdf would absolutely be thrilling.