Alan Gauld said unto the world upon 2005-02-10 02:58:
class Node:
def __init__(self,lines=[]): # here's the zowie BvdB
self.lines = lines def append(self,item): self.lines.append(item)
def parse(self):
# your parsing method here.
Hi all,
I've been following the general approach that Alan suggested and have been happily making much headway. (The code is about twice as long as before and does about 4 times as many things :-) )
At first, I ended up with every single node being a copy of the first one processed. A bit of weeping later, I realized that this is from the feature [?] of Python that default arguments are evaluated just once. (Note the comment added above.)
Happily, I didn't need the default argument. And even if I did, there's the work around from the tutorial <http://docs.python.org/tut/node6.html#SECTION006720000000000000000> that's been under recent discussion in the
python's default argument value handling in functions - weird syntax? problem grappling with the concept
thread.
I may have missed the discussion in that thread but:
<venting>
FOR THE LOVE OF MIKE can someone tell me even one reason why this isn't a misfeature?!?!
</venting>
Sorry for the shouting, but this issue seems to come up a lot. Officially, I do know about it, but it often takes me considerable frustration to realize it's what's ruining my day. I'd be far happier if I could see that there was a good reason for this behaviour. (There'd even be a chance that I'd remember more readily--I hope so, these keyboards are getting expensive.) I'm sure there is one, as I don't believe that Dutchman are particularly given to sadism.
Thanks, and best to all,
Brian vdB
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