raedelson@lion.waterloo.edu (Robyn Edelson) (11/27/89)
I am a novice lisp user and I have a question which doesn't seem to be answered by the documentation I have access to. I am using franz lisp and I need to be able to find out when an arithmetic expression evaluates to either NaN.0 or infinity.0 What I would like to be able to do is some sort of simple test like: (equal (sqrt -4) 'NaN.0) but this doesn't work. I also can't seem to catch it using errset, because it doesn't consider this to be an error. Because of the nature of my program, it is difficult for me to test for all cases which would lead to these values ahead of time. (I also don't know what situations cause these results, and would appreciate this information as well.) Any help would be greatly appreciated! Thanks, Robyn