namespaces

[Bengt Richter]

On Sun, 31 Jul 2005 21:40:14 +0200, Paolino <paolo_veronelli at tiscali.it> wrote:

>George Sakkis wrote:
>
>> Then write a closure. You get both encapsulation and efficience, and as
>> a bonus, customization of the translating function:
>> 
>> import string
>> 
>> def translateFactory(validChars=string.letters+string.digits,
>>                      replaceChar='_'):
>>     all=string.maketrans('','')
>>     badcars=all.translate(all,validChars)
>>     table=string.maketrans(badcars, replaceChar*len(badcars))
>>     def translate(text):
>>         return text.translate(table)
>>     # bind any attributes you want to be accessible
>>     # translate.badcars = badcars
>>     # ...
>>     return translate
>> 
>> 
>> tr = translateFactory()
>> tr("Hel\xfflo")
>
>This is clean,but I suppose it would get cumbersome if I want to have 
>more functions in the namespace/factory and it implies all that bindings 
>in the end.
You are allowed to have more than one factory ;-)

>
>The second point also shows my perplexities about functions namespace:
>
>def function():
>   function.foo='something'
>
>a=function.foo
>
>Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>AttributeError: 'function' object has no attribute 'foo'
>
You have not yet executed the statement function.foo='something'
so you should not expect to see its effect ;-)

>How should I read it? The namespace is half done inside the function?
>
 >>> def function():
 ...     function.foo='something'
 ...
 >>> a=function.foo
 Traceback (most recent call last):
   File "<stdin>", line 1, in ?
 AttributeError: 'function' object has no attribute 'foo'
 >>> vars(function)
 {}

Ok, to make the statement execute, execute function:

 >>> function()
 >>> a=function.foo
 >>> a
 'something'
 >>> vars(function)
 {'foo': 'something'}

Regards,
Bengt Richter