Looking for a text mathematics routine...(smartdraft)

At my previous engineering firm we had a set of cad tools called SmartDraft. There is one thing that I really miss about it, and it was the text mathematics routine.

It would allow you to select a function, then select a text entity with a number, then give you the option to place that text on screen or replace an existing text entity. If you are reading this, I hope you are getting what I am trying to say.

I only know the most basic of lisp. If it has more than 12 lines I just plain get lost. Does anyone have something similar to what I am talking about?

I know a lot of the people who read this board are also on Swampthing. I am also going to post it over there.

TIA

Already got a solution over on Swampthing!

http://www.theswamp.org/index.php?topic=39861.new#new

eg Area of a circle based on text = rad you need to choose parameter ANS somehow

(if (= ans "circarea")
(progn
(setq tp1 (entsel "\nSelect text : "))
(setq tpp1 (entget (car tp1)))
(setq rad (atof (cdr (assoc 1 tpp1))))
(setq area (* 3.1415936 rad))
)
)
(princ area)

then you can do what you want add text change text etc