questions about Exceptions?

[cokofreedom at gmail.com]

In general you should only catch the exceptions you want to catch,
therefore avoiding the issue of catching "unexpected" ones, for
instances the programming unexpectandly closing.

Well, exception handling is expensive (when it catches one) so it
really is up to you. If you are using eval and know it might "EOF"
then you should probably look to handle that. The main IF statement
style I can think of (checking the end of the string) wouldn't be much
of an improvement.

Currently I would be very worried about seeing that code as it breaks
a number of "conventions". However it depends on the importance of the
code to wherever or not you should change this. (Global variable, the
use of Eval, the CATCH ALL except and the setting of a global variable
at the end.)

I've seen a good few (simple and advanced) calculator examples using
python on the NET, it might be worth looking at some to see their
style of coding a calculator to help your own.