can't "pull nodes into" a subgraph

[gordonwoodhull]

In graphviz, the following are equivalent

digraph g {
  subgraph cluster_SG { a -> b}
  a -> c
}

digraph g {
  a -> b
  subgraph cluster_SG { a b }
  a -> c
}

In other words, a node doesn't have to be first declared within a subgraph to be a member of the subgraph; it can be "pulled into" a subgraph by declaring it again within the subgraph.

However, parsing the second example with graphlib-dot, cluster_SG doesn't get declared at all, and a and b are children of the top-level graph. I haven't looked into the code yet, but it seems that the later declarations are ignored, and the subgraph ends up empty and is discarded.

I know the dagre clustering implementation is incomplete, but I hope to read the files anyway, in order to draw the clusters using other algorithms.

I hope to take a look into fixing this, but wanted to post an issue first in case anyone has any clues about this. Thanks!