How would this mythical Ruby code know the orientation of the guideline that you want it to draw ?
There are an infinite number of lines passing through a guide-point.
You can draw a new guideline using the Tape-Measure tool, that passes through a guide-point - but you need to give it some clues...
So if you have two guide-points you can draw a guideline that passes between them,
Of you have only one guide-point you need to pick a second point [e.g. on existing geometry] to give the guideline its orientation.
Or you can pick an existing edge/line in the model to set the guidelines orientation and then pick the guide-point through which it should pass.
None of this needs a script ??
