Abstract
What is a non-strict functional language? Is a non-strict language necessarily lazy? What additional expressiveness brings non-strictness, with or without laziness? This paper tries to shed some light on these questions. First, in order to characterize non-strictness, different evaluation strategies are introduced: strict, lazy, and lenient. Then, using program examples, how these evaluation strategies differ from each other is examined, showing that non-strictness, even without laziness, allows a more general use of recursive definitions. We also report on a small experiment that we performed to examine how, in practice, laziness was used in a number of lazy benchmark programs.
References
[1]
Goldberg, B., Functional programming languages. Computing Surveys. v28 i1. 249-251.
[2]
Traub K. Sequential implementation of lenient programming languages. Technical report MIT/LCS/TR-417, Laboratory for Computer Science, MIT, 1988.
[3]
Tremblay G, Malenfant B. Lenient evaluation and parallelism. Computer Languages 2000;26:27-41.
[4]
Stoy, J., . 1977. MIT Press, Cambridge, MA.
[5]
Osborne R. Speculative computation in multilisp. CRL 90/1, Digital Equipment Corporation, 1990.
[6]
Friedman D, Wise D. CONS should not evaluate its arguments. In: Michaelson S, Milner R, editors. Automata, languages and programming. Edinburgh University Press, Edinburgh, 1976. p. 257-87.
[7]
Henderson, P., . 1980. Prentice-Hall International Series in Computer Science, Englewood Cliffs, NJ.
[8]
Burn G, Hankin C, Abramsky S. The theory of strictness analysis for higher order functions. In: Jones ND, Ganzinger H, editors. Programs as data objects, Lecture Notes in Computer Science, vol. 217, Berlin, Springer, 1985, p. 42-62.
[9]
Hughes R, Wadler P. Projections for strictness analysis. In: Kahn G, editor. Functional prog. lang. and comp. arch., Lecture Notes in Computer Science, vol. 274, Berlin: Springer, 1987, p. 385-407.
[10]
Tremblay G. Parallel implementation of lazy functional languages using abstract demand propagation. Ph.D. Thesis, School of Computer Science, McGill University, November 1994.
[11]
Sondergaard, H. and Sestoft, P., Referential transparency, definiteness and unfoldability. Acta Informatica. v27 i4. 505-517.
[12]
Emerson A. Automated temporal reasoning about reactive systems. In: Moller F, Birtivistle GM, editors. Logics for concurrency-structure versus automata, Lecture Notes in Computer Science, vol. 1043, Berlin: Springer, 1996, p. 41-101.
[13]
Peterson J, Hammond K, editors. Report on the programming language Haskell, a non-strict purely functional language (Version 1.4). Technical report, Yale University, Department of Computer Science, April 1997.
[14]
Nikhil R, Arvind HJ, Aditya S, Augustsson L, Meassen J-W, Zhou Y. pH language reference manual, version 1.0-preliminary. Technical report 369, Laboratory for Computer Science, MIT, January 1995.
[15]
Schmidt D. Denotational semantics: a methodology for language development. Newton, MA: Allyn and Bacon, Inc. 1986.
[16]
Gunter, C., . 1992. MIT Press, Cambridge, MA.
[17]
Field A, Harrison P. Functional programming. Reading, MA: Addison-Wesley Publishers Ltd. 1988.
[18]
Arvind, N.R. and Pingali, K., I-Structures: data structures for parallel computing. TOPLAS. v11 i4. 598-632.
[19]
Clack C, Clayman S, Parrott D. Dynamic cyclic data structures in lazy functional languages. http://www.cs.ucl.ac.uk/staff/C.Clack/papers/NotSubmitted/graph.ps, October 1995.
[20]
Aho A, Hopcroft J, Ullman J. The design and analysis of computer algorithms. Reading, MA: Addison-Wesley Publishing Co. 1974.
[21]
Keller R, Lindstrom G. Applications of feedback in functional progamming. In: Proceedings of the 1981 Conference on Funct. Prog. Lang. and Comp. Arch. 1981, p. 123-30.
[22]
Tremblay G. Exemples de programmation dynamique. Course notes (in french) for an algorithms and data structures course, www.info.uqam.ca/¿¿tremblay/INF4110/prog-dynamique, 1998.
[23]
Allison, L., Application of recursively defined data structures. Australian Computer Journal. v25 i1. 14-20.
[24]
Bird, R., Using circular programs to eliminate multiple traversals of data. Acta Informatica. v21 i4. 239-250.
[25]
Hughes, J., Why functional programming matters. The Computer Journal. v32 i2. 98-107.
[26]
Karczmarczuck, J., Generating power of lazy semantics. Theoretical Computer Science. v187. 203-219.
[27]
Okasaki C. Amortization, lazy evaluation, and persistence: lists with catenation via lazy linking. In: Symposium on Foundations of Computer Science. IEEE, October 1995, p. 646-54.
[28]
Okasaki C. The role of lazy evaluation in amortized data structures. In: International Conference on Functional Programming. ACM, May 1996, p. 62-72.
[29]
Wadler P. How to replace failure by a list of successes: exception handling, backtracking and pattern matching in lazy functional languages. In: Jouannaud JP, editors. Functional Prog. Lang. and Comp. Arch., Lecture Notes in Computer Science, vol. 281, Berlin: Springer, 1985, p. 113-28.
[30]
Hutton, G., Higher-order functions for parsing. Journal of Functional Programming. v2 i3. 323-343.
[31]
Okasaki, C., Functional pearl: even higher-order functions for parsing. Journal of Functional Programming. v8 i2. 195-199.
[32]
Augustsson L. Private communication. April 1995.
[33]
Sekar R, Pawagi S, Ramakrishnan I. Small domains spell fast strictness analysis. In: Proceedings of the ACM Symposium on Principles of Prog. Lang. 1990. p. 169-83.
[34]
Allison, L., Circular programs and self-referential structures. Software-Practice and Experience. v19 i2. 99-109.
[35]
Allison, L., Lazy dynamic-programming can be eager. Information and Processing Letters. v43 i4. 207-212.
[36]
Hartel P, Langendoen K. Benchmarking implementations of lazy functional languages. In: FPCA '93, New York: ACM Press, 1993. p. 341-9.
[37]
Nikhil R. The parallel programming language Id and its compilation for parallel machines. CSG Memo 313, Laboratory for Computer Science, MIT, July 1990.
[38]
Partain W. The nofib benchmark suite of Haskell programs. In: Proceedings of the 1993 Glasgow Workshop on Functional Programming. Berlin: Springer, 1993.
[39]
Tremblay G. Compilation de pH pour une machine parallèle multi-contextes. Note interne de recherche, Dépt. d'informatique, UQAM, juillet 1997.
[40]
Msheik H. Code generation for a functional language targeted to a parallel multithreaded machine. Master's thesis, Dépt. d'Informatique, UQAM, Aoít 2000.
[41]
Augustsson L, Johnsson T. Lazy ML user's manual version 0.999.7. Obtenu via ftp, 1994.
[42]
Turner, D., An overview of miranda. SIGPLAN Notices. v21 i12. 158-166.
[43]
Brus T, van Eekelen M, van Leer M, Plasmeijer M. Clean-a language for functional graph rewriting. In: Kahn G, editor. Funct. Prog. Lang. and Comp. Arch., Lecture Notes in Computer Science, vol. 274, Berlin: Springer, 1987, p. 364-84.
[44]
. 1987. Prentice Hall, Englewood Cliffs, NJ.
[45]
Jones S. How useful is laziness? Posted to comp.lang.functional, August 1995.
[46]
Tremblay G, Gao G. The impact of laziness on parallelism and the limits of strictness analysis. In: Bohm AW, Feo J, editors. High Perf. Funct. Comp., LLNL, CONF-9504126, 1995, p. 119-33.
[47]
Milner, R., A theory of type polymorphism in programming. Journal of Computer and System Science. v17 i3. 348-375.
Recommendations
Lenient evaluation and parallelism
In a companion paper (Tremblay G. Lenient evaluation is neither strict nor lazy. Computer languages 2000; 26:43-66.), we showed that non-strict functional languages were not necessarily lazy. More precisely, non-strict functional languages can be ...
A semantics for lazy assertions
PEPM '11: Proceedings of the 20th ACM SIGPLAN workshop on Partial evaluation and program manipulationLazy functional programming languages need lazy assertions to ensure that assertions preserve the meaning of programs. Examples in this paper demonstrate that previously proposed lazy assertions nonetheless break basic semantic equivalences, because ...
Formally specifying and analyzing a parallel virtual machine for lazy functional languages using Maude
HLPP '11: Proceedings of the fifth international workshop on High-level parallel programming and applicationsPure lazy functional languages are a promising programming paradigm for harvesting massive parallelism, as their abstraction features and lack of side effects support the development of modular programs without unneeded serialization. We give a new ...
Comments
Information & Contributors
Information
Published In
Copyright © Elsevier Science Ltd © 2001.
Publisher
Pergamon Press, Inc.
United States
Publication History
Published: 01 April 2000
Author Tags
Qualifiers
- Article
Contributors
Other Metrics
Bibliometrics & Citations
Bibliometrics
Article Metrics
- 0Total Citations
- 0Total Downloads
- Downloads (Last 12 months)0
- Downloads (Last 6 weeks)0
Reflects downloads up to 05 Feb 2025