Colon in Node names and edges

Hello,

There are a few other open tickets from a bit ago about this. Anyway, I was stumbled over it for a bit as I have nodes which are essentially objects which translate with a colon in it. However, this was difficult to debug as the output was still valid as the Node names stripped everything after the colon although the same does not happen for the edges, ie:

# In:
G.add_edge("(thing :test)", "(thing)", label="A Link")
import sys
from networkx.drawing.nx_pydot import write_dot
write_dot(G, sys.stdout)

# Out:
strict graph  {
    "(thing ";
    "(thing)";
    "(thing :test" -- "(thing)"  [label="A Link"];
}

So I’m using networkx but I know it calls into pydot.to_pydot(…) The problem is that the edge is different to the node meaning you end up with weird duplicates/nodes that are not attached to anything.

[jameshfisher]

I’m guessing this is the same issue:

>>> import pydot
>>> dot = pydot.Dot()
>>> dot.add_node(pydot.Node("x:0"))
>>> dot.get_node("x:0")
[]

Pydot’s job is to hide the dot syntax behind a Python API. As : is part of the dot syntax, if a colon is part of a name, pydot should either escape it, or raise an error. Pydot should provide some pure Python way to specify these “ports” and “compass points”, e.g. pydot.Node(("id", "port", "compass_point")).

[peternowee]

Agreed. pydot/pydot#118 is probably a duplicate of this issue, where the conclusion was the same. I am currently busy looking for work, but hope to pick up pydot work in the evenings once everything stabilizes again. Feel free to open a PR in the mean time.