Quantomatic
Annotations
It would be really cool to be able to put arbitrary text/LaTeX/images on the graph, at arbitrary locations. This could be stored in the graph's userdata.
For example, if a graph implemented a measurement pattern, one could write the measurement pattern as an annotation. Or you could annotate input vertices with dirac notation.
It should, of course, be possible to hide annotations.
We could implement a "notes" node, one that the matcher always ignores, or could implement something like a bang-box that can be connected to however many nodes (which seems like a safer option in terms of making the matcher ignore something.)
I'm struggling a bit to see the use-case for this, especially since rewriting would (currently) clobber this data. I'm not against more annotations, but I think this idea is too generic to be useful.
