introduce a cluster keyword!
https://stackoverflow.com/questions/8366314/drawing-a-border-around-a-set-of-vertices-in-graphviz
Using a special prefix of the identifier of the subgraph to denote clusters is rotten. Introduce real syntax for this! I'd suggest:
cluster foo {
...
}
instead of:
subgraph cluster_foo {
...
}
This new syntax wouldn't invalidate the old rotten convention, but it would avoid new or occasional users to lose time and hairs!
Edited by Pascal J. Bourguignon