Hello.  I am new to this group.  I've done a search for the topic about which 
I'm posting, and while I have found some threads that are relevant, I haven't 
found anything exactly on point that I can understand.  So, I'm taking the 
liberty of asking about something that may be obvious to many readers of this 
group. 

The relevant Python documentation reference is:  
http://docs.python.org/2/reference/expressions.html#boolean-operations.

I'm trying to make sense of the rules of or_test, and_test, and not_test that 
appear in this section.  While I understand the substance of the text in this 
section, it is the grammar definitions themselves that confuse me.  For 
example, I am not clear how an or_test can be an and_test.  Moreover, if I 
follow the chain of non-terminal references, I move from or_test, to and_test, 
to not_test, to comparison.  And when I look at the definition for comparison, 
I seem to be into bitwise comparisons.  I cannot explain this.

Perhaps an example will help put my confusion into more concrete terms.  
Suppose I write the expression if x or y in my code.  I presume this is an 
example of an or_test.  Beyond that, though, I'm not sure whether this maps to 
an and_test (the first option on the right-hand side of the rule) or to the 
or_test "or" and_test option (the second on the right-hand side of the rule).  

If people can offer some thoughts to put me in the right direction (or out of 
my misery), I would appreciate it.

Thank you in advance.
-- 
http://mail.python.org/mailman/listinfo/python-list

Reply via email to