Ownership, Uniqueness, and Immutability

Östlund, Johan; Wrigstad, Tobias; Clarke, Dave; Åkerblom, Beatrice

doi:10.1007/978-3-540-69824-1_11

Cited by 28 publications

(24 citation statements)

References 28 publications

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“…First, a single use of recovery may subsume multiple uses of a scoped approach to borrowing [30], where external uniqueness is preserved by permitting access to only the interior of a particular aggregate within a lexically scoped region of code. Of course, scopeless approaches to borrowing exist with more complex tracking [10,23].…”

Section: Recovering Isolationmentioning

confidence: 99%

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Uniqueness and reference immutability for safe parallelism

Gordon

Parkinson

Parsons

et al. 2012

Proceedings of the ACM International Conference on Object Oriented Programming Systems Languages and Applications

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A key challenge for concurrent programming is that sideeffects (memory operations) in one thread can affect the behavior of another thread. In this paper, we present a type system to restrict the updates to memory to prevent these unintended side-effects. We provide a novel combination of immutable and unique (isolated) types that ensures safe parallelism (race freedom and deterministic execution). The type system includes support for polymorphism over type qualifiers, and can easily create cycles of immutable objects. Key to the system's flexibility is the ability to recover immutable or externally unique references after violating uniqueness without any explicit alias tracking. Our type system models a prototype extension to C# that is in active use by a Microsoft team. We describe their experiences building large systems with this extension. We prove the soundness of the type system by an embedding into a program logic.

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Section: Recovering Isolationmentioning

confidence: 99%

“…Ostlund et al [30] present an ownership type and effect system for a language Joe 3 with the explicit aim of supporting reference immutability idioms by embedding into an ownership type system. Owner polymorphic methods declare the effects they may have on each ownership domain, treating ownership domains as regions [35,36].…”

Section: Related Workmentioning

confidence: 99%

Uniqueness and reference immutability for safe parallelism

Gordon

Parkinson

Parsons

et al. 2012

Proceedings of the ACM International Conference on Object Oriented Programming Systems Languages and Applications

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“…However, linearity causes problems of its own: linear objects cannot be stored in shared data structures, and this tends to restrict expressivity. There is a large literature on less extreme techniques for static control of aliasing: Hogg' [42] among others. In future work we intend to use an off-the-shelf technique for more sophisticated alias analysis.…”

Section: Related Workmentioning

confidence: 99%

Modular session types for distributed object-oriented programming

et al. 2010

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Session types allow communication protocols to be specified typetheoretically so that protocol implementations can be verified by static type-checking. We extend previous work on session types for distributed object-oriented languages in three ways. (1) We attach a session type to a class definition, to specify the possible sequences of method calls. (2) We allow a session type (protocol) implementation to be modularized, i.e. partitioned into separatelycallable methods. (3) We treat session-typed communication channels as objects, integrating their session types with the session types of classes. The result is an elegant unification of communication channels and their session types, distributed object-oriented programming, and a form of typestates supporting non-uniform objects, i.e. objects that dynamically change the set of available methods. We define syntax, operational semantics, a sound type system, and a correct and complete type checking algorithm for a small distributed class-based object-oriented language. Static typing guarantees that both sequences of messages on channels, and sequences of method calls on objects, conform to type-theoretic specifications, thus ensuring type-safety. The language includes expected features of session types, such as delegation, and expected features of object-oriented programming, such as encapsulation of local state. We also describe a prototype implementation as an extension of Java.

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“…So for example, an IGJ map class can require its keys to be immutable, but could permit its values to be either mutable or immutable, and these restrictions will be statically enforced by a generic type system.Östlund et al [17] use an ownership type system to obtain similar flexibility.…”

Section: Object Initialisation and Immutabilitymentioning

confidence: 99%

Understanding the Impact of Collection Contracts on Design

Nelson

Pearce

Noble

2010

Objects, Models, Components, Patterns

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Abstract. Java provides a specification for a user-defined general purpose equivalence operator for objects, but collections such as Set have more stringent requirements. This inconsistency breaks polymorphism: programmers must take care to follow Set's contract rather than the more general Object contract if their object could enter a Set. We have dynamically profiled 30 Java applications to better understand the way programmers design their objects, to determine whether they program with collections in mind. Our results indicate that objects which enter collections behave very differently to objects which do not. Our findings should help developers understand the impact of design choices they make, and guide future language designers when adding support for collections and/or equality.

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Ownership, Uniqueness, and Immutability

Cited by 28 publications

References 28 publications

Uniqueness and reference immutability for safe parallelism

Uniqueness and reference immutability for safe parallelism

Modular session types for distributed object-oriented programming

Understanding the Impact of Collection Contracts on Design

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