Extracting numerical value from range

[Mirko Vukovic]

Hi,

I wrote the following code to convert between Celsius and Fahrenheit scales:

(defun f<->c (&key f c)

  (let ((vf (a-real-betweenv -1e3 1e3 'f))

(vc (a-real-betweenv -1e3 1e3 'c)))

    (when f (assert! (=v vf f)))

    (when c (assert! (=v vc c)))

    (assert! (=v vf (+v (*v 9/5 vc) 32)))

    (list vf vc))) 

When I run it, I get an answer such as

SCREAMER-USER> (value-of (first (f<->c :c 100)))

[F real 212:212]

I am assuming that screamer has narrowed down the range of values 

to 212:212.

How can I extract the values?  Did I overlook something in the documentation,

or do I have to use solve?

Is there a better way to write this problem?

Thanks,

Mirko