[CCC] Object class comment - v2
Dwight Hughes
dwighth at ipa.net
Wed Mar 1 04:02:10 UTC 2000
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Object is the root class for almost all other classes in the class
hierarchy (except for its superclass ProtoObject -- and any other
classes that directly subclass nil). Object inherits the minimum
necessary object behavior defined in ProtoObject and adds the
behavior/protocols common to all normal objects, such as access,
copying, comparison, error handling, message sending, and reflection.
Object has no instance variables, nor should any be added. Several
classes of objects that inherit from Object either have special
implementations (SmallInteger and UndefinedObject for example),
or their structure and layout are known to the VM.
Because Object is the root of the normal inheritance tree, general
utility methods are often defined here to give all objects special
behaviors needed by certain subsystems or applications, or to
respond to certain general test messages.
Class Variables:
DependentsFields an IdentityDictionary
Maps each object to its dependents. Allows all objects to
take part in the dependency mechanism, even if they do not
have an explicit dependents field. See Object>>dependents
and its senders.
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Thanks to all who have contributed their thoughts on this - I hope I
captured the essence of most of your contributions.
-- Dwight
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