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Parents are shared parts of objects: Inheritance and encapsulation in SELF

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LISP and Symbolic Computation

Abstract

The design of inheritance and encapsulation in SELF, an object-oriented language based on prototypes, results from understanding that inheritance allows parents to be shared parts of their children. The programmer resolves ambiguities arising from multiple inheritance by prioritizing an object's parents. Unifying unordered and ordered multiple inheritance supports differential programming of abstractions and methods, combination of unrelated abstractions, unequal combination of abstractions, and mixins. In SELF, a private slot may be accessed if the sending method is a shared part of the receiver, allowing privileged communication between related objects. Thus, classless SELF enjoys the benefits of class-based encapsulation.

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Author notes

  1. David Ungar

    Present address: Sun Microsystems, 2500 Garcia Avenue, 94043, Mountain View, CA

Authors and Affiliations

  1. Computer Systems Laboratory, Stanford University, 94305, Stanford, California

    Craig Chambers, David Ungar, Bay-Wei Chang & Urs Hölzle

Authors
  1. Craig Chambers
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  2. David Ungar
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  3. Bay-Wei Chang
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  4. Urs Hölzle
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Additional information

This work has been generously supported by National Science Foundation Presidential Young Investigator Grant #CCR-8657631, and by Sun Microsystems, IBM, Apple Computer, Cray Laboratories, Tandem Computers, NCR, Texas Instruments, and DEC.

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Chambers, C., Ungar, D., Chang, BW. et al. Parents are shared parts of objects: Inheritance and encapsulation in SELF. Lisp and Symbolic Computation 4, 207–222 (1991). https://doi.org/10.1007/BF01806106

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