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Quasi-static typing

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Satish ThatteAuthors Info & Claims

POPL '90: Proceedings of the 17th ACM SIGPLAN-SIGACT symposium on Principles of programming languages

Pages 367 - 381

https://doi.org/10.1145/96709.96747

Published: 01 December 1989 Publication History

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Abstract

We present a new approach to dynamic typing in a static framework. Our main innovation is the use of structural subtyping for dynamic types based on the idea that possible dynamic typing as a property should be inherited by objects of all types. Two properties of our system set it apart from existing systems which combine static and dynamic typing: all tagging and checking takes place via implicit coercions, and the semantics of dynamic typing is representation independent. The latter property leads to a significant increase in expressive power—for instance it allows us to define a general call-by-value fixpoint operator.

The resulting system—which we call quasi-static typing—is a seamless merger of static and dynamic typing. The system divides programs into three categories: well-typed, ill-typed and ambivalent programs. Ill-typed programs contain expressions that are guaranteed to go wrong. Run-time checking is limited to doubtful function applications in ambivalent programs. Conceptually, quasi-static typing takes place in an unusual two-phase process—a first phase infers types and coercions and a second plausibility checking phase identifies ill-typed programs. The typing rules allow minimal typing judgements and plausibility checking can be characterized as simplification via a canonical set of rewrite rules. The two phase process can therefore be implemented with a one pass algorithm.

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Cited By

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Greenman BDimoulas CFelleisen M(2023)Typed–Untyped Interactions: A Comparative AnalysisACM Transactions on Programming Languages and Systems10.1145/357983345:1(1-54)Online publication date: 5-Mar-2023
https://dl.acm.org/doi/10.1145/3579833
Mooij A(2022)Static type checking without downcast operatorInformation Processing Letters10.1016/j.ipl.2022.106285(106285)Online publication date: May-2022
https://doi.org/10.1016/j.ipl.2022.106285
Greenman BFelleisen MDimoulas C(2019)Complete monitors for gradual typesProceedings of the ACM on Programming Languages10.1145/33605483:OOPSLA(1-29)Online publication date: 10-Oct-2019
https://dl.acm.org/doi/10.1145/3360548
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Index Terms

Quasi-static typing
1. Software and its engineering
  1. Software notations and tools
    1. General programming languages
      1. Language features
        Data types and structures
2. Theory of computation
  1. Semantics and reasoning
    1. Program constructs
      1. Type structures
    2. Program semantics
      1. Denotational semantics
      2. Operational semantics

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Published In

POPL '90: Proceedings of the 17th ACM SIGPLAN-SIGACT symposium on Principles of programming languages

December 1989

401 pages

ISBN:0897913434

DOI:10.1145/96709

Chairman:
Frances E. Allen

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]

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Association for Computing Machinery

New York, NY, United States

Publication History

Published: 01 December 1989

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Cited By

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Greenman BDimoulas CFelleisen M(2023)Typed–Untyped Interactions: A Comparative AnalysisACM Transactions on Programming Languages and Systems10.1145/357983345:1(1-54)Online publication date: 5-Mar-2023
https://dl.acm.org/doi/10.1145/3579833
Mooij A(2022)Static type checking without downcast operatorInformation Processing Letters10.1016/j.ipl.2022.106285(106285)Online publication date: May-2022
https://doi.org/10.1016/j.ipl.2022.106285
Greenman BFelleisen MDimoulas C(2019)Complete monitors for gradual typesProceedings of the ACM on Programming Languages10.1145/33605483:OOPSLA(1-29)Online publication date: 10-Oct-2019
https://dl.acm.org/doi/10.1145/3360548
Fromherz AGiannarakis NHawblitzel CParno BRastogi ASwamy N(2019)A verified, efficient embedding of a verifiable assembly languageProceedings of the ACM on Programming Languages10.1145/32903763:POPL(1-30)Online publication date: 2-Jan-2019
https://dl.acm.org/doi/10.1145/3290376
Florence SYou STov JFindler R(2019)A calculus for Esterel: if can, can. if no can, no can.Proceedings of the ACM on Programming Languages10.1145/32903743:POPL(1-29)Online publication date: 2-Jan-2019
https://dl.acm.org/doi/10.1145/3290374
Emmi MEnea C(2019)Weak-consistency specification via visibility relaxationProceedings of the ACM on Programming Languages10.1145/32903733:POPL(1-28)Online publication date: 2-Jan-2019
https://dl.acm.org/doi/10.1145/3290373
Meyer RWolff S(2019)Decoupling lock-free data structures from memory reclamation for static analysisProceedings of the ACM on Programming Languages10.1145/32903713:POPL(1-31)Online publication date: 2-Jan-2019
https://dl.acm.org/doi/10.1145/3290371
Skorstengaard LDevriese DBirkedal L(2019)StkTokens: enforcing well-bracketed control flow and stack encapsulation using linear capabilitiesProceedings of the ACM on Programming Languages10.1145/32903323:POPL(1-28)Online publication date: 2-Jan-2019
https://dl.acm.org/doi/10.1145/3290332
Miyazaki YSekiyama TIgarashi A(2019)Dynamic type inference for gradual Hindley–Milner typingProceedings of the ACM on Programming Languages10.1145/32903313:POPL(1-29)Online publication date: 2-Jan-2019
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Toro MLabrada ETanter É(2019)Gradual parametricity, revisitedProceedings of the ACM on Programming Languages10.1145/32903303:POPL(1-30)Online publication date: 2-Jan-2019
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