annoying behavior

Elbert Lev elbertlev at hotmail.com
Wed Sep 29 06:10:31 CEST 2004


Michael Hoffman <m.h.3.9.1.without.dots.at.cam.ac.uk at example.com> wrote in message news:<cjcqao$ji0$1 at gemini.csx.cam.ac.uk>...
> Elbert Lev wrote:
> 
> > I think, it would be good, if some sort of warning is given during
> > import, but not during instantiating the instance of the class. At
> > least in a "debug" mode. What really did happen: the bug was reported
> > after the scrip was running for 30 minutes. PyCheck finds it
> > immediatelly. Why not to do the same kind of check in the interpreter?
> 
> Can you post the results of your PyChecker run and the exact input to it?
> 
> I just did a test myself:
> 
> """
> $ cat test1.py
> class X(object):
>      def __init__(self):
>          self.f()
>          self.r = True
> 
>      def f(self):
>          print self.r
> 
> def main():
>      x = X()
> 
> $ pychecker test1.py
> Processing test1...
> 
> Warnings...
> 
> test1.py:10: Local variable (x) not used
> """
> 
> I think that what you want the Python compiler to do is harder than you 
> think it is, and not all cases will be caught unless you actually run 
> the program.
> 
> I've forgotten to assign attributes and variables before using them in 
> the past--it's just something you have to learn not to do.

Here it is:

Processing test...
C:\Python23\python.exe
C:\Python23\Lib\site-packages\pychecker\checker.py
 test.py
  Caught exception importing module test:
    File "C:\Python23\Lib\site-packages\pychecker\checker.py", line
576, in setupMainCode()
      module = imp.load_module(self.moduleName, file, filename, smt)
    File "test.py", line 16
      f = foo("1234")
    File "test.py", line 5, in __init__()
      self.f()
    File "test.py", line 9, in f()
      if self.r:
  AttributeError: foo instance has no attribute 'r'

Warnings...

test:1: NOT PROCESSED UNABLE TO IMPORT

> I think that what you want the Python compiler to do is harder than you 
> think it is, and not all cases will be caught unless you actually run 
> the program.

Sure not all! I tell you more: in many cases after the program was
used for years, it contains errors. This does not stop people debuging
them :) Even if check does not finds all errors it will be very good.
Isn't this what Python is about - fast and fun programming, not
frustration. After all, if I want troubles, I always can use C or Java
:))



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