research-article

κDOT: scaling DOT with mutation and constructors

Authors:

Ondřej LhotákAuthors Info & Claims

Scala 2018: Proceedings of the 9th ACM SIGPLAN International Symposium on Scala

Pages 40 - 50

https://doi.org/10.1145/3241653.3241659

Published: 17 September 2018 Publication History

Abstract

Scala unifies concepts from object and module systems by allowing for objects with type members which are referenced via path-dependent types. The Dependent Object Types (DOT) calculus of Amin et al. models only this core part of Scala, but does not have many fundamental features of Scala such as strict and mutable fields. Since the most commonly used field types in Scala are strict,the correspondence between DOT and Scala is too weak for us to meaningfully prove static analyses safe for Scala by proving them safe for DOT.

A DOT calculus that can support strict and mutable fields together with constructors that do field initialization would be more suitable for analysis of Scala. Toward this goal, we present κDOT, an extension of DOT that supports constructors and field mutation and can emulate the different types of fields in Scala. We have proven κDOT sound through a mechanized proof in Coq. We present the key features of κDOT and its operational semantics and discuss work-in-progress toward making κDOT fully strict.

References

[1]

Nada Amin, Samuel Grütter, Martin Odersky, Tiark Rompf, and Sandro Stucki. 2016. The Essence of Dependent Object Types. In A List of Successes That Can Change the World - Essays Dedicated to Philip Wadler on the Occasion of His 60th Birthday (Lecture Notes in Computer Science), Sam Lindley, Conor McBride, Philip W. Trinder, and Donald Sannella (Eds.), Vol. 9600. Springer, 249-272.

[2]

Nada Amin, Adriaan Moors, and Martin Odersky. 2012. Dependent Object Types. In 19th International Workshop on Foundations of Object-Oriented Languages.

[3]

Nada Amin and Tiark Rompf. 2017. Type soundness proofs with definitional interpreters. In Proceedings of the 44th ACM SIGPLAN Symposium on Principles of Programming Languages, POPL 2017, Paris, France, January 18-20, 2017, Giuseppe Castagna and Andrew D. Gordon (Eds.). ACM, 666-679.

Digital Library

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Nada Amin, Tiark Rompf, and Martin Odersky. 2014. Foundations of path-dependent types. In Proceedings of the 2014 ACM International Conference on Object Oriented Programming Systems Languages & Applications, OOPSLA 2014, part of SPLASH 2014, Portland, OR, USA, October 20-24, 2014, Andrew P. Black and Todd D. Millstein (Eds.). ACM, 233-249.

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Adriaan Moors, Frank Piessens, and Martin Odersky. 2008. Safe type-level abstraction in Scala. In International Workshop on Foundations of Object-Oriented Languages (FOOL 2008).

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Martin Odersky. 2016. Scaling DOT to Scala -- Soundness. http://www.scala-lang.org/blog/2016/02/17/scaling-dot-soundness.html.

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Cited By

Martres GRichard-Foy JDoeraene S(2021)Pathless Scala: a calculus for the rest of ScalaProceedings of the 12th ACM SIGPLAN International Symposium on Scala10.1145/3486610.3486894(12-21)Online publication date: 17-Oct-2021
https://dl.acm.org/doi/10.1145/3486610.3486894
Kabir ILi YLhoták O(2020)ιDOT: a DOT calculus with object initializationProceedings of the ACM on Programming Languages10.1145/34282764:OOPSLA(1-28)Online publication date: 13-Nov-2020
https://dl.acm.org/doi/10.1145/3428276
Rapoport MLhoták O(2019)A path to DOT: formalizing fully path-dependent typesProceedings of the ACM on Programming Languages10.1145/33605713:OOPSLA(1-29)Online publication date: 10-Oct-2019
https://dl.acm.org/doi/10.1145/3360571

Index Terms

κDOT: scaling DOT with mutation and constructors
1. Software and its engineering
  1. Software notations and tools
    1. Formal language definitions

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Dependent Object Types (DOT) is intended to be a core calculus for modelling Scala. Its distinguishing feature is abstract type members, fields in objects that hold types rather than values. Proving soundness of DOT has been surprisingly challenging, ...
ιDOT: a DOT calculus with object initialization

The Dependent Object Types (DOT) calculus serves as a foundation of the Scala programming language, with a machine-verified soundness proof. However, Scala's type system has been shown to be unsound due to null references, which are used as default ...

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cover image ACM Conferences

Scala 2018: Proceedings of the 9th ACM SIGPLAN International Symposium on Scala

September 2018

82 pages

ISBN:9781450358361

DOI:10.1145/3241653

General Chair:
Sebastian Erdweg,
Program Chair:
Bruno C. d. S. Oliveira

Copyright © 2018 ACM.

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Published: 17 September 2018

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SIGPLAN

ICFP '18: 23nd ACM SIGPLAN International Conference on Functional Programming

September 28, 2018

MO, St. Louis, USA

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Overall Acceptance Rate 5 of 6 submissions, 83%

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Cited By

Martres GRichard-Foy JDoeraene S(2021)Pathless Scala: a calculus for the rest of ScalaProceedings of the 12th ACM SIGPLAN International Symposium on Scala10.1145/3486610.3486894(12-21)Online publication date: 17-Oct-2021
https://dl.acm.org/doi/10.1145/3486610.3486894
Kabir ILi YLhoták O(2020)ιDOT: a DOT calculus with object initializationProceedings of the ACM on Programming Languages10.1145/34282764:OOPSLA(1-28)Online publication date: 13-Nov-2020
https://dl.acm.org/doi/10.1145/3428276
Rapoport MLhoták O(2019)A path to DOT: formalizing fully path-dependent typesProceedings of the ACM on Programming Languages10.1145/33605713:OOPSLA(1-29)Online publication date: 10-Oct-2019
https://dl.acm.org/doi/10.1145/3360571

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