Mel wrote:
<snip>
This is an artifact of the interactive interpreter,
True. You can avoid the artifact by wrapping the test in a function:
Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41)
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
class A():
... def __repr__ (self):
... return b
...
def is_defined (obj):
... try:
... obj
... except NameError:
... return False
... return True
...
a = A()
if is_defined (a):
... print "`a` is defined"
... else:
... print "`a` is not defined"
...
`a` is defined
if is_defined (b):
... print "`b` is defined"
... else:
... print "`b` is not defined"
...
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'b' is not defined
At the cost of it not quite working when the function is called with an
undefined name. I suppose the print statements could be crafted to make it
look better.
Mel.
No clue what you're trying to accomplish here. The exception inside the
function is_defined() will never fire; the method always returns True.
You're getting an exception during the attempt to call such a function,
and so of course there's no point in putting the if test around that either.
This may be the last time I try to read such complexity in an
interactive transcript. It took a couple of tries before I got the
indentation understood. I thought that is_defined() was intended to be
a method inside the class.
DaveA
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