Crystal Reports Evaluation for AND OR

Message

   Hi,

For an OR statement, when does the evaluation occur? After the first value or the second? In 'C' terminology, is OR equivelant to '|' or '||' 

conversely, is AND in Crystal equivelant to '&' or '&&' ?

My question arises from a conditional statement which wasn't working as expected (not that it's directly related to the above Q but it got me thinking). e.g.
(simplified)
if (x = x)  or (x = y)   where x = 1; y = null

should return true as one of the two conditions are met, but in my case, it returned false.

What's up with this!?

Cheers!
Ant 