LISP routine for maximum path lengths

Some time ago someone on one of these groups asked for a lisp routine to
limit the length of a polyline to a specified length and I said I could use
something like that.

My first stab at it is now available on my site's lisp page. While not
exactly what was discussed, this one reports the developed length after each
point is added, and draws a circle centered on the last valid point of the
polyline when the next point would have made it too long. The radius of the
circle indicates the distance remaining under the maximum from the last
valid point.

The routine is called "length.lsp". I imagine using it for exit travel
distances, fire hose coverage, and rough layout of fire access routes, etc.
As usual for me, it has no error handler, dialog boxes, etc.