[Zope] Newbie - passing a list to an External Method

[Dylan Reinhardt]

On Thu, 2003-04-17 at 13:23, Passin, Tom wrote:
> [ Dylan Reinhardt]
> > a = [1,2.3]
> > b = a
> > b = None
> > # now the value of a is None!
> > 
> 
> That is not right.  a retains its value as expected.  To prove it,
> here's  a transcript from an IDLE session, with Py2.1.3 -
> 

Ugh... there's nothing like making a newbie error when you try to point
out a newbie error.  I probably shouldn't speculate and offer help at
the same time.  Thanks for keeping me honest. :-)


> This is different from re-assigning the variable to reference something
> else like None.

You're right... no amount of in-place changes to a list object will
probably produce the error the OP is seeing.  Theorizing how that change
might have been a side effect of something else was just off-base.

But we can still go back to theory #1: something in that external method
is *directly* re-assigning the "lines" variable to a non-sequence type
like None.

Dylan