Feature Request: Extracting sub-graphs from GFA

[samarendra-pani]

An interesting feature for GFAs are extracting sub-graphs from GFAs. This will help with smaller alignment tasks where some reads can be aligned to the subgraph.

Possible features:

• Extract graph from node X to node Y (where both nodes are scaffold nodes).
• Extract the surrounding graph when a node path is given (for extracting the sub-graph that an alignment maps to).
• Extract graph based on chromosomal coordinates.

[fawaz-dabbaghieh]

I didn't notice this, but for extracting a subgraph around a node, this can easily be done, as I already implemented that in my other GFA tools. The other two I have to think about, because when you have two nodes, then you need to find all nodes in between, and I am not sure what the best way to do that.