[Tutor] problems pickling functions

[Arild B. Næss]

Hi,

I'm writing a program for tagging which requires a long time to  
calculate the parameters. I have therefore tried to write a long  
program that pickles all the data, and pickles a function that uses  
these parameters to tag an input sentence.

But I'm having trouble with loading the function. The odd thing is  
that it works fine in the interpreter to pickle and load a function:

 >>> import pickle
 >>> def simple():
...     print "This works"
...
 >>> f=open("simple.txt","w")
 >>> pickle.dump(simple,f)
 >>> f.close()
 >>> s()
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
NameError: name 's' is not defined
 >>> f=open("simple.txt","r")
 >>> s=pickle.load(f)
 >>> s()
This works

However when I try to do this with the script simple.py (with the  
exact same commands as above) it doesn't work:

$ cat simple.py

import pickle

def simple():
     print "This works"

f = open("simple.txt","w")
pickle.dump(simple,f)
f.close()

$ python simple.py
$ python
Python 2.5 (r25:51918, Sep 19 2006, 08:49:13)
[GCC 4.0.1 (Apple Computer, Inc. build 5341)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
 >>> import pickle
 >>> f2 = open("simple.txt","r")
 >>> s
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
NameError: name 's' is not defined
 >>> s = pickle.load(f2)
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/pickle.py", line 1370, in load
     return Unpickler(file).load()
   File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/pickle.py", line 858, in load
     dispatch[key](self)
   File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/pickle.py", line 1090, in load_global
     klass = self.find_class(module, name)
   File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/pickle.py", line 1126, in find_class
     klass = getattr(mod, name)
AttributeError: 'module' object has no attribute 'simple'
 >>>

I don't get this error message, and I'm annoyed – because I'm used to  
that things that work in the interpreter also work when written as a  
program.

Can anyone help?

regards,
Arild Næss