[Patches] [ python-Patches-555251 ] Mutable object change flag

[noreply@sourceforge.net]

Patches item #555251, was opened at 2002-05-12 19:22
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=305470&aid=555251&group_id=5470

Category: Core (C code)
Group: Python 2.3
>Status: Closed
Resolution: None
Priority: 1
Submitted By: Raymond Hettinger (rhettinger)
Assigned to: Nobody/Anonymous (nobody)
Summary: Mutable object change flag

Initial Comment:
This patch is a proof-of-concept for marking state 
changes in mutable objects.  It is meant as a simpler, 
faster alternative to a full built-in observer pattern.

Here's the whole protocol:
Mutable objects choosing to implement the protocol 
provide a writable attribute, cachevalid, which is 
initialized to zero.  Upon any update to the object, 
the attribute is reset to zero.  Callers who set the 
attribute to one can later check to see if an update 
has occurred (as indicated by a zero).

>>> a = list('abcd')
>>> a.cachevalid
0
>>> a.cachevalid=1
>>> a.cachevalid
1
>>> a[2] = 'k'
>>> a.cachevalid
0

The proof-of-concept patch is implemented only for 
lists.  A production version would need to include 
dictionaries.



----------------------------------------------------------------------

Comment By: Martin v. Löwis (loewis)
Date: 2002-10-07 16:32

Message:
Logged In: YES 
user_id=21627

Raymond, are you still interested in this approach?

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=305470&aid=555251&group_id=5470