Documentation of 'control' on rules

[adam-antonik]

The section at the bottom of https://github.com/TeamCohen/TensorLog/wiki/Program mentions 'control' on rules, and gives an example using it:
r1,r2 = b.rule_ids("r1 r2") ... b.rules += aunt(X,Y) <= uncle(X,Z) & wife(Z,Y) // r1 b.rules += aunt(X,Y) <= parent(X,Z) & sister(Z,Y) // r2 b.rules += aunt(X,Y) <= uncle(X,Z) & wife(Z,Y) // (weight(F) | description(X,D) & feature(X,F))
I'm afraid I don't really understand what is going on here. Could you expand on what this 'control' is and does?