Where can I use any sort of formula?

 I had stareted a thread about calling out a polyline length.  https://forum.bricsys.com/discussion/23910

I ended up inserting a field in the leader, with the text being the length property of the polyline.  This polyline represented a piping run, and now I would like to include a length for the vertical part of the run.  Note that this is just a 2D drawing.

I see in AutoCAD, there is a way to write an equation to sum things in a field.  It is somewhat convoluted, but is possible.  See this discussion,

But, I don't see the same choices in BricsCAD. So, I wonder if there is any similar approach that can work with BricsCAD. 

I can currently show the horizontal and vertical distances as separate fields, by putting the vertical component as the length of a separate line I drew elsewhere in the drawing just for this purpose.  But, I can't figure out how to sum the lengths. I know I can use a lisp routine, and put a static text, but I need it associative  Is there any way to do this in BricsCAD?

-Joe