Mart'in Abadi and Luca Cardelli. A theory of primitive objects: Untyped and first-order systems. In Theoretical Aspects of Computer Software, pages 296--320. Springer-Verlag, April 1994.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....by the type inference system via a subsumption rule. Our extension gives the following (positive) consequences: 21 ffl objects with extra methods can be used in any context where an object with fewer methods might be used, ffl our subtyping relation does not cause the shortcomings described in [AC96b], ffl we do not loose any feature of LCO. We also extend the set of objects and we present an alternative operational semantics. Our reduction rules look up method bodies more directly than bookeeping of LCO and deal with possible errors. This semantics was inspired by [Bel94] where the ....

....n : Delta An alternative could be enriching method names with labels in kinds, but we think this would be a too heavy mechanism without enough benefits to counterbalance. In this section we will present three examples: the first shows how our subtyping relation works on a critical example of [AC96b]. The second example gives a simple object, typable in our calculus, but not typable in the original calculus. Then we compare this calculus with the proposal of [FM95a] where a different form of width subtyping has been presented. Example 3.3 Given the following objects: hx=self :0; mv x ....

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M. Abadi and L. Cardelli. A Theory of Primitive Objects: Untyped and First-Order System. Information and Computation, 125(2):78--102, March 1996.

....18, 10, 11] A few programming languages based on process calculi have been purposed. Some, such as Pict [19] or Oz [10, 11] have gained some prominence. The TyCO object calculus on which the abstract machine described in this paper is based is very reminescent of Abadi and Cardelli s calculus [1, 2]. Here as in TyCO objects are primitive and represented as sums of labelled methods. Labelled method invocation (messages in TyCO ) are also present. The calculus has an extra method update operation which is not present in TyCO and is fully sequential. TyCO has the same computational power as the ....

M. Abadi and L. Cardelli. A Theory Of Primitive Objects: Untyped and First-Order System. Information and Computation, 125(2):78--102, 1996.

....proposes a general typology of the uses of # calculus. While enough of the # calculus is presented below to support the examples used, a full exploration of the formalism would be impossible here and the reader is directed to the literature for a more substantial treatment of the # calculus [2, 3, 4, 5]. As far a possible, the notation used in the following examples is consistent with this literature to facilitate the reference. 3.1. Schema development An important feature of any formal method in software development is the ability to capture the results of an analysis in a precise, ....

M. Abadi and L. Cardelli. A theory of primitive objects: Untyped and first-order systems. Information and Computation, 125(2):78--102, 1996.

....4 and 5 develop the fully abstract translation in the presence of subtyping and some concluding remarks are made in Section 6. Due to space considerations, all proofs are omitted from this paper. 2 Preliminaries 2. 1 Object Calculi (Source Languages) The object calculi we consider are based on [3, 5] extended with a ground type of booleans (as in [10] The following grammar defines the terms (ranged over by lower case letters a, b) and types (ranged over by upper case letters A,B) of the object calculi: j [l i = x i : A)b i ] j a:l j a:l ( x : A)b A; B : X j Top j Bool j [l i : ....

M. Abadi and L. Cardelli. A theory of primitive objects: Untyped and first-order systems. In Proceedings of Theoretical Aspects of Computer Software, pages 296--320, Sendai, Japan, April 1994. Springer-Verlag.

....methods, but which are not yet installed in any object. Premethods are functions that explicitly depend on the object itself, typically assumed to be the first parameter to the function. Following this idea, Abadi and Cardelli encoded classes in a pure object system using records of premethods [3]; these ideas are also used by Reppy and Riecke [29] In this approach, a class is an object that contains a record of premethods and a constructor function used to package these premethods into objects. The primary advantage of the record of premethods encoding is that it does not require a ....

M. Abadi and L. Cardelli. A theory of primitive objects: Untyped and first-order systems. Information and Computation, 125(2):78--102, 1996. Earlier version appeared in TACS '94 proceedings, LNCS 789. 463

....3In all our examples we will take the convention that identifiers denoting objects start with a lower case letter, whereas identifiers denoting generators start with an upper case letter. 4Neglecting syntactic differences, this binding operator corresponds to the cr 0 operator as defined in [Abadi Cardelli 94] SAlthough not explicitly present in the syntax, throughout the examples we will make use of predefined strings understanding an add message to concatenate them with other strings, and an equal method for equality testing. isThatYou ( Joe ) to the object returns the TRUE object as a result. ....

....and semantics of the calculus, so we don t need an additional type system for this purpose. 13 From a pragmatic point of view, the difference lies in the motivation of the calculus: Fisher and Mitchell developed a new type system in order to solve problems in existing type systems (such as [Abadi Cardelli 94] while we have developed a two layered calculus in order to cope with the encapsulation problems in current object oriented languages (cf. Snyder 87] Steyaert De Meuter 95] When comparing both calculi more closely, one can found two other differences: A minor difference between both ....

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Abadi, M. & Cardelli, L. - 1994. A Theory of Primitive Objects: Untyped and First-Order Systems. TACS '94 Proceedings, Springer-Verlag.

....expressible in OPUS and vice versa. We even think that it is possible to define our calculus on top of XN. However, we do feel that XN catcutus is too low level as a model for expressing and investigating object oriented concepts. Another calculus that seems close to ours is the one proposed by (Abadi et al. 1994). Just like OPUS, it is not based on lambda calculus, although it subsumes lambda calculus. But as opposed 5 This also compromises object based encapsulation, because it allows a method to be selected and temporarily stored somewhere, and later on this method can be retrieved and applied in a ....

M. Abadi and L. Cardelli. A Theory of Primitive Objects: Untyped and Firstorder Systems. Theoretical Aspects of Computing Software '94 Proceedings, SpringerVerlag,

....is fundamentally different from most of the previous work on the semantics of objects. Much of that work has focused on interpreting object systems and the underlying mechanisms via record extensions of lambda calculi [19, 41, 66, 58, 67] or as native object calculi (with a record flavor) [1, 2, 3]. In our semantics, types are simply the names of entities declared in the program; the collection of types forms a dag, which is specified by the programmer. The collection of types is static during evaluation and is only used for field and method lookups and casts. The evaluation rules ....

Abadi, M. and L. Cardelli. A theory of primitive objects --- untyped and firstorder systems. In Hagiya, M. and J. C. Mitchell, editors, Theoretical Aspects of Computer Software, volume 789 of Lecture Notes in Computer Science, pages 296--320. Springer-Verlag, April 1994.

....Department of Computer Science, University of Edinburgh, The King s Buildings, Edinburgh, EH9 3JZ, U.K. Electronic mail: bcp dcs.ed.ac.uk. Models for various object oriented features have also been given using different techniques [MHF93, Aba93, CGL92, Cas92, Car92, AC94b, AC94a, Mit90, Wan87, Wan88, Wan89, etc. The core calculus underlying all of these models is an extension of Girard s higher order polymorphic calculus, System F , with subtyping. Many of the ideas behind this system, called F ( F omegasub ) are due to Cardelli, particularly to his ....

Mart'in Abadi and Luca Cardelli. A theory of primitive objects: Untyped and first-order systems. In Theoretical Aspects of Computer Software (TACS), Sendai, Japan, 1994.

.... Internet: BRICS brics.dk BRICS publications are in general accessible through World Wide Web and anonymous FTP: http: www.brics.dk ftp: ftp.brics.dk pub BRICS Objects as mobile processes Hans Huttel and Josva Kleist October 29, 1996 Abstract The object calculus of Abadi and Cardelli [AC96, AC94b, AC94a] is intended as model of central aspects of object oriented programming languages. In this paper we encode the object calculus in the asynchronous calculus without matching and investigate the properties of our encoding. 1 Introduction In [AC96, AC94b, AC94a] Abadi and Cardelli investigate ....

....calculus of Abadi and Cardelli [AC96, AC94b, AC94a] is intended as model of central aspects of object oriented programming languages. In this paper we encode the object calculus in the asynchronous calculus without matching and investigate the properties of our encoding. 1 Introduction In [AC96, AC94b, AC94a] Abadi and Cardelli investigate several versions of an object oriented calculus (the calculus) with respect to its type system. The primary motivation behind the calculus is to find a simple foundation for object oriented languages, just as the calculus forms a foundation for functional ....

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Martin Abadi and Luca Cardelli. A theory of primitive objects -- untyped and first-order systems. Information and Computation, 125(2):78--102, 1996.

....the temporal modalities of the logic CTL [BAMP83] We investigate the connection between the type system Ob 1 : and the mu calculus, providing a translation of types into modal formulae and an ordering on formulae that is sound w.r.t. to the subtype ordering of Ob 1 : 1 Introduction In [AC94a, AC94b, AC94c, AC96] Abadi and Cardelli present and investigate several versions of the calculus, a calculus for describing central features of object oriented programs, with particular emphasis on various type systems. In this paper we present a modal logic for describing dynamic properties of terms in the object ....

....a Curry Howard style result in that it allows us to view calculus terms as realizers of certain mu calculus formulae. 2 The calculus and its reduction semantics There are various versions of the calculus. In this paper we shall consider what is essentially the simple object calculus of [AC94b] with booleans added. The set of object terms, Obj, is defined by the following abstract syntax: a : l i = x i :A i )b i ] i2I objects j x self variables j a:l method activation j a:l ( x:A)b method override j fold(A; a) j unfold(a) recursive fold unfold j if (a; a; a) j true j false ....

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Martin Abadi and Luca Cardelli. A theory of primitive objects -- untyped and first-order systems. In Theoretical Aspects of Computer Software, pages 296--320. Springer-Verlag, 1994.

....that provide the musician with flexible ways of interaction. In [15] the # calculus was extended with the notion of constraint. In this paper we consider the addition of objects and messages synchronized by constraints. Several concurrent objects calculi have been proposed recently [17] 16] [1]. In these models the interactions of concurrent processes (or objects) are synchronized essentially through one of two mechanisms: the use of a channel and message passing . In TyCO, for instance, an object a [l : # y)P] can be seen as a process P which is suspended until some message ....

M. Abadi and L. Cardelli (1994). "A Theory of Primitive Objects: Untyped and First-order Systems." Proceedings of Theoretical Aspects of Computer Software.

....the body which contains a let statement that makes x equal to x.arg in the original expression, assuming x is the bound variable. That is: x) b reduces to [arg = x) x.arg val = x) let x = x.arg in b ] which is then reduced again. This expansion was first introduced by Abadi and Cardelli [5]. To reduce a function application the argument field is updated to be associated with the actual argument, then the method containing the body is invoked. This translation of function abstractions into the object calculus is described by Abadi and Cardelli [5] I could have implemented ....

....introduced by Abadi and Cardelli [5] To reduce a function application the argument field is updated to be associated with the actual argument, then the method containing the body is invoked. This translation of function abstractions into the object calculus is described by Abadi and Cardelli [5]. I could have implemented functions directly using ML, but using objects was useful to test that the calculus copes well when lots of objects, such as repeated function applications, are involved. Compilation into Intermediate Code The intermediate code is based largely on the code designed by ....

M Abadi and L Cardelli, A Theory of Primitive Objects - Untyped and FirstOrder Systems, DEC Systems Research Center.

....lexi cally scoped language, by the desire for a simple object model that would scale up to distributed computation, and by the availability of a sophisticated network objects implementation technology. The Obliq object primitives were designed in parallel with work on the type theory of objects [Abadi, Cardelli 1994]; distributed scoping and distributed semantics, however, are not treated there. Status Obliq has been available at Digital SRC for about a year. In addition to incidental programming, it has been used extensively as a scripting language for algorithm animation [Brown 1994] and 3D graphics ....

M. Abadi and L. Cardelli. A theory of primitive objects: untyped and firstorder systems. Proc. Theoretical Aspects of Computer Software. Springer-Verlag.

....995 PM cally scoped language, by the desire for a simple object model that would scale up to distributed computation, and by the availability of a sophisticated network objects implementation technology. The Obliq object primitives were designed in parallel with work on the type theory of objects [Abadi, Cardelli 1994]; distributed scoping and distributed semantics, however, are not treated there. Status Obliq has been available at Digital SRC for about a year. In addition to incidental programming, it has been used extensively as a scripting language for algorithm animation [Brown 1994] and 3D graphics ....

M. Abadi and L. Cardelli. A theory of primitive objects: untyped and firstorder systems. Proc. Theoretical Aspects of Computer Software. Springer-Verlag.

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Mart'in Abadi and Luca Cardelli. A theory of primitive objects: Untyped and first-order systems. In Theoretical Aspects of Computer Software, pages 296--320. Springer-Verlag, April 1994.

No context found.

Abadi, M. & Cardelli, L. - 1994. A Theory of Primitive Objects: Untyped and First-Order Systems. TACS `94 Proceedings, Springer-Verlag.

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M. Abadi and L. Cardelli. A Theory of Primitive Objects: Untyped and Firstorder Systems. Theoretical Aspects of Computing Software '94 Proceedings, SpringerVerlag, 1994

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Mart'in Abadi and Luca Cardelli. A theory of primitive objects: Untyped and first-order systems. Information and Computation, 125(2):78 -- 102, March 1996.

No context found.

Abadi, M. & Cardelli, L. - 1994. A Theory of Primitive Objects: Untyped and First-Order Systems. TACS `94 Proceedings, Springer-Verlag.

No context found.

M. Abadi and L. Cardelli. A Theory of Primitive Objects: Untyped and First-Order System. Information and Computation, 125(2):78--102, March 1996.

No context found.

M. Abadi and L. Cardelli. A theory of primitive objects: Untyped and first order system. Information and Computation, 125(2):78--102, 1996.

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Mart'in Abadi and Luca Cardelli. A theory of primitive objects: Untyped and first-order systems. In Theoretical Aspects of Computer Software (TACS), Sendai, Japan, 1994.

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M. Abadi and L. Cardelli. A theory of primitive objects: untyped and firstorder systems. In Proc. Theor. Aspects of Computer Software, Sendai, Japan, 1994.

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Martin Abadi, Luca Cardelli. A Theory of Primitive Objects - Untyped and First-Order Systems. Information and Computation, 125(2), pp.78-102, 1996.

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