[EMAIL PROTECTED] a écrit :
<OT>
Martin, would you _please_ learn to quote properly ? top-posting and
keeping the whole text of the previous posts are two really annoying
practices. TIA
</OT>
> I'm less confused. If someone can explain the wisdom of this design,
> I'd be grateful.
Since there's no distinct declarations of names, all names are by
default created in the local namespace when bound in this namespace.
Else you couldn't shadow global names in a local namespace... OTHO, free
variables are looked up in all enclosing namespaces, so in a a
non-nested function, names used but not bound in the local namespace are
looked up in the global one.
> If someone can explain why the following compiles successfully, I'd be
> even more grateful:
>
> def get_toks( text ):
> global line_ptr, last_line
> while line_ptr < last_line:
> while char_ptr < len(text[line_ptr]):
> if matches_EOI():
> tokens.append( Token(EOI) )
> elif matches_EOL():
> tokens.append( Token(EOL) )
> line_ptr += 1
> char_ptr = 0
FWIW, this code is incomplete. Please post the minimal *working* code
reproducing your problem. Here, I had to define all the missing symbols
to test your script.
> Shouldn't "char_ptr" be flagged as an error, appearing in line 4
> before being a lhs in the last line?
Note that such errors are raised at runtime, not during compilation
(FWIW, I wonder why, since the use of the name is detected at
compilation IIRC).
The error appears as long as line_ptr < last_line before calling the
function. Now when line_ptr >= last_line, there is no error. So I
conclude that UnboundLocalErrors are not raised until the offending line
is actually executed.
Now while I don't know if it's a bug or a well-defined behaviour (I
almost never rebind globals in functions..), I agree that this is at
least weird since the compilation phase already tags the name as local
wherever it's bound in the function.
Here's a minimal code reproducing the problem:
cnt = 1
test = 1 # set this to 0 to have an UnboundLocalError in wontdo()
retest = 1
def wontdo():
global test
global restest
while test < retest:
while cnt:
cnt = cnt - 1
test += 1
Some guru on this ?
NB : tested with
Python 2.5.1 (r251:54863, May 2 2007, 16:56:35)
[GCC 4.1.2 (Ubuntu 4.1.2-0ubuntu4)] on linux2
(snip)
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