Behavioural Types for Memory and Method Safety in a Core Object-Oriented Language

Bravetti, Mario; Francalanza, Adrian; Golovanov, Iaroslav; Hüttel, Hans; Jakobsen, Mathias; Kettunen, Mikkel Klinke; Ravara, António

doi:10.1007/978-3-030-64437-6_6

Cited by 9 publications

(16 citation statements)

References 28 publications

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“…We introduce an object-oriented calculus with classes and enumeration types, similar to previous work on Mungo [3,6,21,22,37].…”

Section: The Languagementioning

confidence: 99%

“…As opposed to previous type systems for Mungo [3,21,22] the type system presented here performs a global analysis of the program, in order to maintain a global view of aliasing while guaranteeing correct objects' states. This means that instead of relying on compositionality during type checking, we must explore the entire program graph.…”

Section: Type Systemmentioning

confidence: 99%

“…These method orderings, or protocols, are often defined in varying degrees of formality through documentation or comments, which makes the process difficult and error-prone. Work has been undertaken to include these protocols in the program itself with the introduction of typestates for object-oriented languages [1,3,8,21].…”

Section: Introductionmentioning

confidence: 99%

“…Common to many of these approaches is that they rely on a linear type system, where only a single reference to an object can exist, thus eliminating-or limiting-aliasing. In Mungo [3,21] linearity is always enforced, whereas other approaches in languages such as Plaid [2] and Vault [7] allow limited aliasing, while preserving compositionality of the type system such that each class can be type checked in isolation [11,24]. These approaches often require programmer annotations to deal with aliasing control or they simply eliminate aliasing altogether.…”

Section: Introductionmentioning

confidence: 99%

“…This is more representative of the sort of aliasing that can occur in real-world programs. In this work we treat typestates in a similar fashion to the line of work on Mungo [3,21] and along the same lines, we introduce Papaya, an implementation of a typestate-based type system for Scala.…”

Section: Introductionmentioning

confidence: 99%

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Papaya: Global Typestate Analysis of Aliased Objects

Jakobsen

Ravier

Dardha

2021

23rd International Symposium on Principles and Practice of Declarative Programming

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Typestates are state machines used in object-oriented programming to specify and verify correct order of method calls on an object. To avoid inconsistent object states, typestates enforce linear typing, which eliminates-or at best limits-aliasing. However, aliasing is an important feature in programming, and the state-of-the-art on typestates is too restrictive if we want typestates to be adopted in real-world software systems.In this paper, we present a type system for an object-oriented language with typestate annotations, which allows for unrestricted aliasing, and as opposed to previous approaches it does not require linearity constraints. The typestate analysis is global and tracks objects throughout the entire program graph, which ensures that well-typed programs conform and complete the declared protocols. We implement our framework in the Scala programming language and illustrate our approach using a running example that shows the interplay between typestates and aliases. CCS CONCEPTS• Theory of computation → Formalisms; • Software and its engineering → Object oriented languages.

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“…We introduce an object-oriented calculus with classes and enumeration types, similar to previous work on Mungo [3,6,21,22,37].…”

Section: The Languagementioning

confidence: 99%

Section: Type Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Papaya: Global Typestate Analysis of Aliased Objects

Jakobsen

Ravier

Dardha

2021

23rd International Symposium on Principles and Practice of Declarative Programming

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A Session Subtyping Tool

Bacchiani

Bravetti

Lange

et al. 2021

Lecture Notes in Computer Science

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Session types are becoming popular and have been integrated in several mainstream programming languages. Nevertheless, while many programming languages consider asynchronous fifo channel communication, the notion of subtyping used in session type implementations is the one defined by Gay and Hole for synchronous communication. This might be because there are several notions of asynchronous session subtyping, these notions are usually undecidable, and only recently sound (but not complete) algorithmic characterizations for these subtypings have been proposed. But the fact that the definition of asynchronous session subtyping and the theory behind related algorithms are not easily accessible to non-experts may also prevent further integration. The aim of this paper, and of the tool presented therein, is to make the growing body of knowledge about asynchronous session subtyping more accessible, thus promoting its integration in practical applications of session types.

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