this file might help
From this conversation . http://www.grasshopper3d.com/xn/detail/2985220:Comment:1791398.
The paths are written so that they contain a single intersect point and the path indices describes which intersect(s) belong(s) to which two lines in the form {lineindexA;lineindexB} and paths with nothing in them don't touch.
Using path{A;B}, from the original list of curves that were input, lineA would be found at index(A) and lineB would be found at index(B)