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mgedmin / objgraph

Visually explore Python object graphs
http://mg.pov.lt/objgraph/
MIT License
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Consolidate graph creation #10

Closed pcostell closed 9 years ago

pcostell commented 9 years ago

Right now there are multiple places that have very similar functionality. For example show_graph and find_chain both search for a chain from the supplied object to a predicate (in find_chain the predicate is user specified, in show_graph it is a module). This results in some weird cases where to show a set of chains, find_chain is called to collect all nodes that are involved in the chain, then show_graph calculates all chains again and just uses the already built chains as a filter.

Instead I imagine this could be consolidated into something more like:

find_graph(...) and find_graph(..., shortest_path=True) where the logic is more or less the same but shortest_path just has an early end condition. Then find_chain is obsoleted by find_graph(..., shortest_path=True) and show_chain is obsoleted by show_graph which only has to contain the logic for creating the DOT format.

mgedmin commented 9 years ago

Issue #5 is about this, more or less.

It's unlikely I'll find the time to work on it any time soon, and I'm not very confident in my API design skills.

mgedmin commented 9 years ago

FWIW

This results in some weird cases where to show a set of chains, find_chain is called to collect all nodes that are involved in the chain, then show_graph calculates all chains again and just uses the already built chains as a filter

We need to calculate the chain again if we want to represent it, since edge labels are computed on the fly (e.g. if a dictionary X refers to an object Y, we need to iterate over X.items() in order to find the key K where X[K] is Y). The way culling is implemented in show_chain should mean that _show_graph doesn't traverse unnecessary nodes.

We could eliminate the need to do a double traverse if we store edge labels in a data structure while we're traversing the graph in find_chain. We'd need to store those somewhere. Maybe we could have a Graph object that represents the nodes and edges that ought to be drawn.

pcostell commented 9 years ago

Yes I was thinking something Graph object like. I'll close in favor of keeping the discussion on issue #5.