A Theory of Objects

Abadi, Martı́n; Cardelli, Luca

doi:10.1007/978-1-4419-8598-9

Cited by 656 publications

(579 citation statements)

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“…This algorithm is both more efficient and easier for a programmer to understand than a breadth-first algorithm that would otherwise be required. 1 …”

Section: Dispatch Modelmentioning

confidence: 99%

“…Our calculus borrows ideas from several previous object calculi, but the differences between PMD and previous object models are too great to use a straightforward extension of a previous calculus. For example, only one previous calculus that we know of supports imperative updates of methods [1]. However, this calculus, like most others [3], compiles away delegation by simply copying methods from the delegatee into the delegator.…”

Section: Formal Modelmentioning

confidence: 99%

“…The most significant difference with all previous calculi is our modeling of multiple dispatch through roles on objects; this makes the common approach of modeling objects as records of methods inappropriate [9,1,3]. Although a few object calculi model multi-methods [12,4], they all model multi-methods as external functions that dispatch over a fixed dispatch hierarchy, while PMD allows the developer to change the methods that are applicable to an object, as well as to modify the inheritance hierarchy at run time.…”

Section: Formal Modelmentioning

confidence: 99%

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Prototypes with Multiple Dispatch: An Expressive and Dynamic Object Model

Salzman

Aldrich

2005

ECOOP 2005 - Object-Oriented Programming

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Abstract. Two object-oriented programming language paradigmsdynamic, prototype-based languages and multi-method languagesprovide orthogonal benefits to software engineers. These two paradigms appear to be in conflict, however, preventing engineers from realizing the benefits of both technologies in one system. This paper introduces a novel object model, prototypes with multiple dispatch (PMD), which seamlessly unifies these two approaches. We give formal semantics for PMD, and discuss implementation and experience with PMD in the dynamically typed programming language Slate. OverviewWe begin the paper by describing a motivating example that shows the limitations of current, popular object-oriented languages for capturing how method behavior depends on the interaction between objects and their state. The example shows that multi-methods can cleanly capture how behavior depends on the interaction between objects, while dynamic, prototype-based languages can cleanly capture how behavior depends on object state. Unfortunately, unifying highly dynamic, prototype-based languages with multi-methods is hard, because traditional multi-methods assume a static class hierarchy that is not present in dynamic prototype-based languages.In section 3 we describe Prototypes with Multiple Dispatch (PMD), an object model that combines the benefits of dynamic, prototype-based languages with multi-methods. PMD supports both paradigms by introducing a role concept that links a slot within an object to a dispatch position on a method, and defining a dynamic multi-method dispatch mechanism that traverses the graph of objects, methods, and roles to find the most specific method implementation for a given set of receiver objects.Section 4 defines the PMD model more precisely using operational semantics. Section 5 demonstrates the expressiveness of PMD through the standard library of Slate, a dynamically-typed language that implements the PMD object model. Section 6 describes an efficient algorithm for implementing dispatch in Slate. Section 7 describes related work, and section 8 concludes.

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“…This algorithm is both more efficient and easier for a programmer to understand than a breadth-first algorithm that would otherwise be required. 1 …”

Section: Dispatch Modelmentioning

confidence: 99%

Section: Formal Modelmentioning

confidence: 99%

Section: Formal Modelmentioning

confidence: 99%

See 1 more Smart Citation

Prototypes with Multiple Dispatch: An Expressive and Dynamic Object Model

Salzman

Aldrich

2005

ECOOP 2005 - Object-Oriented Programming

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“…The UML description of classes by state-machines combines mechanisms for dynamic process creation similarly to object calculi [1,10,20,16] with synchronization mechanisms as in process calculi [9,6,14].…”

Section: Related Workmentioning

confidence: 99%

A Fully Abstract Semantics for UML Components

Boer

Bonsangue

Steffen

et al. 2005

Formal Methods for Components and Objects

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Abstract. We present a fully abstract semantics for components. This semantics is formalized in terms of a notion of trace for components, providing a description of the component externally observable behavior inspired by UML sequence diagrams. Such a description abstracts from the actual implementation given by UML state-machines. Our full abstraction result is based on a may testing semantics which involves a composition of components in terms of cross-border dynamic class instantiation through component interfaces.

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“…The descends relation among objects is the reflexive, transitive closure of the declared inheritance relation. As in other classless languages (LaLonde et al, 1986;Lieberman, 1986;Ungar and Smith, 1987;Chambers, 1992;Abadi and Cardelli, 1996), objects play the roles of both classes and instances, and isa accordingly plays the roles of both inheritance and instantiation. For example, in the modules of Fig.…”

Section: Informal Semanticsmentioning

confidence: 99%

Modular Statically Typed Multimethods

Millstein

Chambers

1999

ECOOP’ 99 — Object-Oriented Programming

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Multimethods offer several well-known advantages over the single dispatching of conventional object-oriented languages, including a simple solution to the binary method problem, a natural implementation of the strategy design pattern, and a form of open objects that enables easy addition of new operations to existing classes. However, previous work on statically typed multimethods whose arguments are treated symmetrically has required the whole program to be available in order to perform typechecking. We describe Dubious, a simple core language including first-class generic functions with symmetric multimethods, a classless object model, and modules that can be separately typechecked. We identify two sets of restrictions that ensure modular type safety for Dubious as well as an interesting intermediate point between these two. We have proved each of these modular type systems sound. C 2002 Elsevier Science (USA)

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A Theory of Objects

Cited by 656 publications

References 0 publications

Prototypes with Multiple Dispatch: An Expressive and Dynamic Object Model

Prototypes with Multiple Dispatch: An Expressive and Dynamic Object Model

A Fully Abstract Semantics for UML Components

Modular Statically Typed Multimethods

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