•Unit of Behavior
–Inheritance of Implementation
•SI via a single Superclass
•MI through Aspects
[Interfaces and
Mixins]
–Methods for The Class
•A Function
–Methods for Instances
•A Member Function
•Unit of Metadata
–Mutable Repository
–Arbitrarily extensible
–Reflectively queryable
•Unit of
Structure
–Constructor of Objects
–Single Inheritance of Layout of Fields
•Reference Types (Slots)
•Value Types (Bits/Structs)
–Intrinsic Aggregation and MI Composition through Interfaces
•Unit of
Privilege/Scope
–Namespace
•Container of shared fields (variables)
•Scope for Message Selectors
–Inheritance of Scope
•SI via a single Superscope
•MI through Importing
–