validation for float input

Chris,

Thanks for all your comments and for the proposed link. It
was unknown to me.

It's true, that my IsFloat implemtation is windows specific.
On my win platform:

print PlusInf -> 1.#INF
print MinInf -> -1.#INF
print NotANumber -> -1.#IND

Note the NaN value! However I do not know how to get it
from a literal.

From IDLE:

Python 2.3.3 (#51, Dec 18 2003, 20:22:39) [MSC v.1200 32 bit (Intel)] on win32

Regards.

Jean-Michel Fauth, Switzerland