On understanding data abstraction, revisited

Abstract

In 1985 Luca Cardelli and Peter Wegner, my advisor, published an ACM Computing Surveys paper called "On understanding types, data abstraction, and polymorphism". Their work kicked off a flood of research on semantics and type theory for object-oriented programming, which continues to this day. Despite 25 years of research, there is still widespread confusion about the two forms of data abstraction, abstract data types and objects. This essay attempts to explain the differences and also why the differences matter.

References

1. N. Adams and J. Rees. Object-oriented programming in Scheme. In Proceedings of the ACM Conf. on Lisp and Functional Programming, pages 277--288, 1988.
2. P. America. A behavioral approach to subtyping object-oriented programming languages. In Proceedings of the REX Workshop/School on the Foundations of Object-Oriented Languages, volume 173 of Lecture Notes in Computer Science, 1990.
3. J. Bergstra and J. Tucker. Initial and final algebra semantics for data type specifications: Two characterisation theorems. Research Report IW 142, Stichting Mathematisch Centrum, 1980.
4. G. M. Birtwistle. DEMOS: a system for discrete event modelling on Simula. Springer--Verlag, 1987.
5. D. Box. Essential COM (DevelopMentor Series). Addison-Wesley Professional, 1998.
6. C. Boyapati, B. Liskov, and L. Shrira. Ownership types for object encapsulation. SIGPLAN Notices, 38(1):213--223, 2003.
7. R. Burstall and J. Goguen. Putting theories together to make specifications. In International Joint Conferences on Artificial Intelligence, pages 1045--1058. Department of Computer Science, Carnegie-Mellon University, 1977.
8. P. Canning, W. Cook, W. Hill, and W. Olthoff. Interfaces for strongly-typed object-oriented programming. In Proceedings of ACM Conf. on Object-Oriented Programming, Systems, Languages and Applications, pages 457--467, 1989.
9. L. Cardelli. A semantics of multiple inheritance. In Semantics of Data Types, volume 173 of Lecture Notes in Computer Science, pages 51--68. Springer-Verlag, 1984.
10. L. Cardelli and P. Wegner. On understanding types, data abstraction, and polymorphism. Computing Surveys, 17(4):471--522, 1986.
11. C. Chambers. Object-oriented multi-methods in Cecil. In ECOOP '92: Proceedings of the European Conference on Object-Oriented Programming, pages 33--56. Springer-Verlag, 1992.
12. A. Church. The Calculi of Lambda Conversion. Princeton University Press, 1941.
13. W. Cook. A Denotational Semantics of Inheritance. PhD thesis, Brown University, 1989.
14. W. Cook. Object-oriented programming versus abstract data types. In Proceedings of the REX Workshop/School on the Foundations of Object-Oriented Languages, volume 173 of Lecture Notes in Computer Science, 1990.
15. B. C. d. S. Oliveira. Modular visitor components: A practical solution to the expression families problem. In S. Drossopoulou, editor, 23rd European Conference on Object Oriented Programming (ECOOP), 2009.
16. O.-J. Dahl, B. Myhrhaug, and K. Nygaard. The SIMULA 67 common base language. Technical report, Norwegian Computing Center, 1970. Publication S-22.
17. H.-D. Ehrich. On the theory of specification, implementation and parameterization of abstract data types. J. ACM, 29(1):206--227, 1982.
18. A. Filinski. Declarative continuations and categorical duality. Master's thesis DIKU Report 89/11, University of Copenhagen, 1989.
19. J. Gibbons. Unfolding abstract datatypes. In MPC '08: Proceedings of the 9th international conference on Mathematics of Program Construction, pages 110--133, 2008.
20. J. Goguen, J. Thatcher, and E. Wagner. An initial algebra approach to the specification, correctness, and implementation of abstract data types. Current Trends in Programming Methodology, IV:80--149, 1978.
21. J. Gosling, B. Joy, G. Steele, and G. Bracha. Java(TM) Language Specification. Addison-Wesley Professional, 2005.
22. D. N. Gray, J. Hotchkiss, S. LaForge, A. Shalit, and T. Weinberg. Modern languages and Microsoft's Component Object Model. Commun. ACM, 41(5):55--65, 1998.
23. C. A. Gunter and J. C. Mitchell, editors. Theoretical aspects of object-oriented programming: types, semantics, and language design. MIT Press, 1994.
24. J. Guttag. The Specification and Application to Programming of Abstract Data Types. Report, University of Toronto, Computer Science Department, 1975.
25. C. Hewitt, P. Bishop, I. Greif, B. Smith, T. Matson, and R. Steiger. Actor induction and meta-evaluation. In POPL '73: Proceedings of the 1st annual ACM SIGACT-SIGPLAN symposium on Principles of programming languages, pages 153--168. ACM, 1973.
26. C. A. R. Hoare. Proof of correctness of data representation. Acta Informatica, 1:271--281, 1972.
27. J. Hogg, D. Lea, A. Wills, D. deChampeaux, and R. Holt. The Geneva convention on the treatment of object aliasing. SIGPLAN OOPS Messenger, 3(2):11--16, 1992.
28. D. Ingalls. The Smalltalk-76 programming system. In POPL, pages 9--16, 1978.
29. B. Jacobs. Objects and classes, co-algebraically. In Object orientation with parallelism and persistence, pages 83--103. 1996.
30. S. P. Jones. Haskell 98 Language and Libraries: The Revised Report. Cambridge University Press, 2003.
31. S. P. Jones. Classes, Jim, but not as we know them. type classes in Haskell: what, why, and whither. ECOOP Keynote, 2009.
32. B. W. Kernighan and D. Ritchie. C Programming Language (2nd Edition). Prentice Hall PTR, 1988.
33. S. Krishnamurthi, M. Felleisen, and D. P. Friedman. Synthesizing object-oriented and functional design to promote re-use. In In European Conference on Object-Oriented Programming, pages 91--113. Springer, 1998.
34. B. Liskov. Keynote address - data abstraction and hierarchy. In OOPSLA '87: Addendum to the Proceedings on Object-oriented programming systems, languages and applications (Addendum), pages 17--34, 1987.
35. B. Liskov. A history of CLU. In History of programming languages-II, pages 471--510. ACM, 1996.
36. B. Liskov, R. Atkinson, T. Bloom, E. Moss, J. C. Schaffert, R. Scheifler, and A. Snyder. CLU Reference Manual. Springer-Verlag, 1981.
37. B. Liskov and S. Zilles. Programming with abstract data types. SIGPLAN Notices, 9(4):50--59, 1974.
38. K. C. Louden. Programming Languages: Principles and Practice. Wadsworth Publ. Co., 1993.
39. D. B. MacQueen. Modules for Standard ML. In Conference on LISP and Functional Programming, 1984.
40. B. Mahr and J. Makowsky. An axiomatic approach to semantics of specification languages. In Proceedings of the 6th Conference on Theoretical Computer Science, volume 145 of Lecture Notes in Computer Science, pages 211--219. Springer-Verlag, 1983.
41. R. Milner. Communication and Concurrency. Prentice-Hall, 1989.
42. R. Milner, M. Tofte, and R. Harper. The definition of Standard ML. MIT Press, 1990.
43. J. C. Mitchell. Concepts in Programming Languages. Cambridge University Press, 2001.
44. J. C. Mitchell and G. D. Plotkin. Abstract types have existential type. In Proceedings of the ACM Symp. on Principles of Programming Languages. ACM, 1985.
45. P. Müller, A. Poetzsch-Heffter, and G. T. Leavens. Modular invariants for layered object structures. Sci. Comput. Program., 62(3):253--286, 2006.
46. D. A. Naumann. Observational purity and encapsulation. Theor. Comput. Sci., 376(3):205--224, 2007.
47. M. Odersky, L. Spoon, and B. Venners. Programming in Scala: A Comprehensive Step-by-step Guide. Artima Inc, 2008.
48. M. Odersky and M. Zenger. Independently extensible solutions to the expression problem. In Proceedings FOOL 12, 2005. http://homepages.inf.ed.ac.uk/wadler/fool.
49. U. S. D. of Defense. Reference manual for the Ada programming language. ANSI/MIL-STD-1815 A, 1983.
50. B. C. Pierce. Types and Programming Languages. MIT Press, 2002.
51. T. W. Pratt and M. V. Zelkowitz. Programming languages: design and implementation. Prentice-Hall, 1995.
52. J. C. Reynolds. User-defined types and procedural data structures as complementary approaches to data abstraction. In New Advances in Algorithmic Languages, pages 157--168. INRIA, 1975.
53. M. L. Scott. Programming Language Pragmatics. Morgan Kaufmann, 2000.
54. R. Sebesta. Concepts of Programming Languages, Eighth Edition. Addison-Wesley, 2007.
55. J. F. Shoch. An overview of the programming language Smalltalk-72. SIGPLAN Notices, 14(9):64--73, 1979.
56. G. Steele. LAMBDA: The ultimate declarative. Technical Report AIM-379, MIT AI LAB, 1976.
57. A. B. Tucker and R. E. Noonan. Programming Languages: Principles and Paradigms, Second Edition. McGraw-Hill Higher Education, 2007.
58. P. Wadler. The expression problem. Mail to the java-genericity mailing list, 1998.
59. P. Wadler and S. Blott. How to make ad-hoc polymorphism less ad hoc. In POPL '89: Proceedings of the 16th ACM SIGPLAN-SIGACT symposium on Principles of programming languages, pages 60--76. ACM, 1989.
60. N. Wirth. Programming in Modula-2. Springer-Verlag, 1983.
61. W. A. Wulf, R. L. London, and M. Shaw. An introduction to the construction and verification of Alphard programs. IEEE Transactions on Software Engineering, SE-24(4), 1976.
62. S. N. Zilles. Procedural encapsulation: A linguistic protection mechanism. SIGPLAN Notices, 8(9):142--146, 1973.

Index Terms

• Software and its engineering

  • Software notations and tools

    • General programming languages

      • Language features

        • Abstract data types

        • Classes and objects