[CCC] Object class comment
Andrew P. Black
black at cse.ogi.edu
Tue Feb 29 00:55:24 UTC 2000
At 14:22 -0500 2000.2.28, Norton, Chris wrote:
>In addition to the other fine responses to your question (ProtoObject is the
>superclass of Object, et. al), I believe that people also define Proxy
>objects by subclassing nil (UndefinedObject), rather than Object. Proxy
>objects are common ...
Unfortunately, since UndefinedObject is itself a subclass of Object,
making Proxy a subclass of UndefinedObject does not achieve the
desired effect. (It does achieve one _undesired_ effect -- making
all the Proxy objects print as nil!
I believe that the reasons for the creation of ProtoObject include
the need to have a place to put Proxy objects that is not a subclass
of Object. ObjectOut and ImageSegmentRootStub are two proxy objects
in the image that are subclsses of ProxyObject. Marcel's Trampoline
code should probably be modified so that Trampoline is a subclass of
ProtoObject rather than UndefinedObject.
More information about the Squeak-dev
mailing list
|