[Pyobjc-dev] [ pyobjc-Bugs-785980 ] Inheriting from NSObject blocks visibility of attributes

[SourceForge.net <no...@so...>]

Bugs item #785980, was opened at 2003-08-09 18:30
Message generated for change (Tracker Item Submitted) made by Item Submitter
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=114534&aid=785980&group_id=14534

Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Steven Arnold (stevena)
Assigned to: Nobody/Anonymous (nobody)
Summary: Inheriting from NSObject blocks visibility of attributes

Initial Comment:
Classes that inherit from Foundation.NSObject do not 
correctly see methods in superclasses before the one that 
inherited from NSObject.  However, note that dir does show 
the attribute!  Consider the following code snippet:

    import Foundation
    class ListManager:
        def init( self ):
            return self
        def key_for_index( self, index ):
            print "INDEX = ", index
    
    class foo( Foundation.NSObject, ListManager ):
        def init( self ):
            ListManager.init( self )
            return self
    
    i = foo.alloc().init()
    if 'key_for_index' in dir( i ):
        present = "is"
    else:
        present = "is not"
    
    print "dir shows that key_for_index %s an attribute of i" 
% present
    i.key_for_index( 5 )

If you run this code, you get the following:

    >>> print "dir shows that key_for_index %s an attribute 
of i" % present
    dir shows that key_for_index is an attribute of i
    >>> i.key_for_index( 5 )
    Traceback (most recent call last):
      File "<stdin>", line 1, in ?
    AttributeError: 'foo' object has no attribute 
'key_for_index'


However, if you modify the code to avoid inheriting from 
Foundation.NSObject, you get the expected behavior:

    import Foundation
    class ListManager:
        def init( self ):
            return self
        def key_for_index( self, index ):
            print "INDEX = ", index
    
    class foo( ListManager ):
        def init( self ):
            ListManager.init( self )
            return self
    
    i = foo()
    if 'key_for_index' in dir( i ):
        present = "is"
    else:
        present = "is not"
    
    print "dir shows that key_for_index %s an attribute of i" 
% present
    i.key_for_index( 5 )

The result:

    >>> print "dir shows that key_for_index %s an attribute 
of i" % present
    dir shows that key_for_index is an attribute of i
    >>> i.key_for_index( 5 )
    INDEX =  5


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

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=114534&aid=785980&group_id=14534