[Python-Dev] Advice in stat.py
Guido van Rossum
guido@zope.com
Sun, 29 Jul 2001 13:00:59 -0400
> On Sat, Jul 28, 2001 at 09:54:21AM -0400, Guido van Rossum wrote:
> > > Worse, according to the Reference Manual,
>
> > > The "from" form with "*" may only occur in a module scope.
>
> > I don't know when that snuck in, but it's not enforced. If we're
> > serious, we should at least add a warning!
>
> Eh, last I looked, you and Jeremy were most serious about this :) It came up
> during the nested-scopes change in 2.1, where it was first made illegal, and
> later just illegal in the presence of a nested scope:
>
> (without future statement)
> >>> def spam(x):
> ... from stat import *
> ... def eggs():
> ... print x
> ...
> <stdin>:1: SyntaxWarning: local name 'x' in 'spam' shadows use of 'x' as
> global in nested scope 'eggs'
> <stdin>:1: SyntaxWarning: import * is not allowed in function 'spam' because
> it contains a nested function with free variables
>
> (with future statement)
> >>> def spam(x):
> ... from stat import *
> ... def eggs():
> ... print x
> ...
> File "<stdin>", line 2
> SyntaxError: import * is not allowed in function 'spam' because it contains
> a nested function with free variables
>
> > I'll add a bug report.
Hm. I'm curious why it was not made a warning without a nested
function. Perhaps because too much 3rd party code would trigger the
warning? (I have a feeling that lots of amateur programmers are a lot
fonder of import * than they should be :-( ).
> Should we warn about exec (without 'in' clause) in functions as well ?
>
> (without future statement)
> >>> def spam(x,y):
> ... exec y
> ... def eggs():
> ... print x
> ...
> <stdin>:1: SyntaxWarning: local name 'x' in 'spam' shadows use of 'x' as
> global in nested scope 'eggs'
> <stdin>:1: SyntaxWarning: unqualified exec is not allowed in function 'spam'
> it contains a nested function with free variables
>
> (with future statement)
> >>> def spam(x,y):
> ... exec y
> ... def eggs():
> ... print x
> ...
> File "<stdin>", line 2
> SyntaxError: unqualified exec is not allowed in function 'spam' it contains
> a nested function with free variables
>
> The warnings *only* occur in the presence of a nested scope, though.
That one is just fine I think.
--Guido van Rossum (home page: http://www.python.org/~guido/)