[Python-Dev] Making mutable objects readonly

2001年1月31日 13:01:24 +0100

Guido van Rossum wrote:
>> [ESR]
> > For different reasons, I'd like to be able to set a constant flag on a
> > object instance. Simple semantics: if you try to assign to a
> > member or method, it throws an exception.
> >
> > Application? I have a large Python program that goes to a lot of effort
> > to build elaborate context structures in core. It would be nice to know
> > they can't be even inadvertently trashed without throwing an exception I
> > can watch for.
>> Yes, this is a good thing. Easy to do on lists and dicts. Questions:
>> - How to spell it? x.freeze()? x.readonly()?

How about .lock() and .unlock() ?

> - Should this reversible? I.e. should there be an x.unfreeze()?

Yes. These low-level locks could be used in thread programming
since the above calls are C level functions and thus thread safe
w/r to the global interpreter lock.

> - Should we support something like this for instances too? Sometimes
> it might be cool to be able to freeze changing attribute values...

Sure :)
Eric, could you write a PEP for this ?
-- 
Marc-Andre Lemburg
______________________________________________________________________
Company: http://www.egenix.com/
Consulting: http://www.lemburg.com/
Python Pages: http://www.lemburg.com/python/