Sangiorgi, D. (1996). An interpretation of typed objects into typed - calculus. In FOOL 3, New Brunswick.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....The first class contains works that provide semantics to objects by encoding them into process calculi. Works in the second class study calculi where primitives for objects and for concurrent processes coexist. Systematic translations of objects into calculus can be found, for instance, in [Wal95,HK96,San98,KS98]. Works that belong to the second approach are much closer to what we do here. Among these it is worth to mention the approaches of [Vas94,PT95,FMLR00] which, given a name passing calculus, build high level constructors distinctive of object oriented languages. A complementary approach is followed ....

D. Sangiorgi. An interpretation of typed objects into typed -calculus. IC, 143(1):34--73, 1998.

....asynchronous messages that select a branch of the sum. The aim of the work is to provide an operational semantics and a polymorphic type system that detects message not understood errors, and the work includes a type inference algorithm. 6 1.2. Non uniform objects 4. Sangiorgi de nes V [San98] a typed calculus that communicates variant values, constructed from names and variant tags, and includes a case constructor to decompose the variant values. The aim is the study of type systems, objects, and subtyping in a calculus . 5. Boudol de nes the Blue Calculus [Bou98] a program ....

....in Blue [Dal99] A very successful model of objects is Abadi and Cardelli s calculus [AC96] actually a family of several typed calculi all based on a common untyped calculus. To import its various type systems into the calculus, H uttel, Kleist and Sangiorgi de ne encodings [HK96, Kle00, San98] DiBlasio and Fisher [DF96] and Gordon and Hankin [GH98] choose a di erent path, adding concurrent constructors to the calculus. Another setting where objects are studied as processes are Actors [HBS73, Agh86] Actors have unique identities and communicate by asynchronous message passing; ....

Davide Sangiorgi. An interpretation of typed objects into typed -calculus. Journal of Information and Computation, 143(1):34-73, 1998. Earlier version published as Rapport de Recherche RR-3000, INRIA Sophia-Antipolis, 1996.

....so they are not reflected in the calculus. A number of refined type systems for calculi have been studied, addressing polymorphism [FLMR97, LW95, PS97, Tur96, Vas94] directionality [Ode95, PS96] linearity and receptiveness [Ama97, KPT96, San97] deadlock freedom [Kob97] object encodings [San96], confluence [Nie96, NS97] type inference [Gay93, VH93] and other phenomena (this is far from exhaustive) Each allows some particular behavioural discipline of processes to be expressed. It may be useful to contrast typing for calculi with the more standard typing for calculi. A simply typed ....

Davide Sangiorgi. An interpretation of typed objects into typed -calculus. Rapport de Recherche RR-3000, INRIA Sophia-Antipolis, August 1996.

....is useful for studying compositional synchronisation in such models. 1. Introduction With the ability to directly model dynamic reference structures, process algebras such as the calculus ( Milner92, Milner99] and its variations have been used to model concurrent objects ( Walker95, Jones93, Sangi96, H uttel96, Zhang97] Some researchers ( Schne97, Zhang98a, Zhang98b] have also applied it to model compositional concurrent objects in the aspect oriented programming style ( Aksit92, Holmes97] attempting to avoid the inheritance anomaly [McHale94] One of the important issues with such ....

Davide Sangiorgi. (1996). "An Interpretation of Typed Objects into Typed calculus", INRIA Technical Report RR-3000.

....in the context of # and #. An alternative approach (used, for example, in [PS93] gives an okay type to all expressions which are well behaved in this way, e.g. x: okay or #, # x: #. The di#erence is essentially notational, and we prefer the more concise form as used, for example, in [San96]. 11 3.4.1 Type Safety of Code We start with rules for establishing the type safety of a piece of code. There are ten rules, each rule being concerned with a single code primitive, a fact that we use later on to prove results about the type safety system. The first four rules deal with ends, ....

Davide Sangiorgi. An interpretation of typed objects into typed #-calculus. Technical Report RR-3000, Inria, Institut National de Recherche en Informatique et en Automatique, 1996.

....of liveness properties) Thus, the types should capture the flow of the processes, being themselves processes [Bou98, GH99, HVK98, IK01, Kob00, Yos96] Note that some of these systems assign types to processes, not to names. In a name passing calculus of objects such as T yCO [VT93] or # V a [San98], processes denote the behaviour of a community of interacting objects, where each object has a location identified by a name. Statically detecting method not understood errors is a more delicate problem in systems of (possibly distributed) concurrent objects. The usual records as types paradigm ....

Davide Sangiorgi. An interpretation of typed objects into typed #-calculus. 143(1):34--73, 1998. Earlier version published as Rapport de Recherche RR3000, INRIA, August 1996.

....background In the next section we give the semantics of jeblik as an encoding into some calculus. In Figure 9, we introduce a monadic asynchronous calculus [HT92, Bou92] equipped with: i) name testing; ii) labeled values, called variants, used recently for encoding objects [San98]; iii) a case destructor construct over variants values; iv) a wrong construct used to indicate that a run time error has occurred. Substitutions, ranged over by , are functions from names to values; for an expression e which could be either a process or a value, e is the result of applying ....

....some well known syntactic sugar for presenting the encoding: we use (i) tuples x, also in labeled 26 values l h zi and patterns l ( z) and (ii) parameterized recursive de nitions. Both can be faithfully represented in our core calculus, tuples in a type safe manner by means of variants [San98], and recursion up to weak bisimulation in terms of replication [Mil93] In Figures 10 13, we present an encoding from jeblik terms into calcu lus terms parameterized on two names. In an encoded jeblik term [ a] p , the parameters are used for returning its result (p) and for ....

D. Sangiorgi. An Interpretation of Typed Objects into Typed -Calculus. Information and Computation, 143(1):34-73,

....Email: fhans,kleistg cs.auc.dk 1 our encoding is not fully abstract with respect to weak bisimulation in the calculus and consider what constraints must be imposed on the calculus to get full abstractness. The work presented in this paper is thus related to the results achived by Sangiorgi in [San96] but arose independently. A main difference is in the choice of calculus; Sangiorgi employs the matching construct of the calculus, whereas the encoding presented in this paper does not and restricts its attention to the asynchronous calculus. An encoding of the calculus into the asynchronous ....

....the use of self variables. The object a shows how an object can modify itself by performing a method override on a self variable. 3 The asynchronous calculus The calculus [PW92] has previously shown its ability to encode both the calculus [Mil92] and certain object oriented languages [Wal95, San96]. In [Wal95] Walker encoded a variant of the programming language POOL [Ame89] into the calculus and in [San96] Sangiorgi investigates another encoding of the calculus into the calculus. Sangiorgi shows how to encode the calculus in a type correct way into an extended version of the cal ....

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Davide Sangiorgi. An interpretation of typed objects into typed -calculus. Research Report RR-3000, INRIA Sophia Antipolis, August 1996.

....future research We have dened and shown the correctness of IFA and BTA for FOb 1: In the future, it seems worth: 1. extending our results to more powerful and realistic object calculi; 2. scaling up to annotated type systems the existing translations from calculi to and calculi, see e.g. [6, 24], in particular to reduce non interference for the former to non interference for the latter. Acknowledgements We are grateful to F. van Raamsdonk and the anonymous referees for their constructive comments. Thanks to D. Teller and S. Villemot for implementing the annotated calculi. The rst author ....

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Information and Computation, 143(1):3473, May 1998.

....objects in defined in [8] we claim that those abstractions can be uniformly applied to every object creation. Moreover, These abstractions can be transposed to other process calculi, and in particular to distributed versions of the calculus [14, 9, 2] and to other interpretation of objects [13]. The principal advantage of defining standardized behaviors of migration , is that we can define migrating objects from objects designed in an non distributed language without adding any explicit thread of control, thus providing a flexible and simple way to automatically add migration features ....

Davide Sangiorgi. An interpretation of typed objects into typed -calculus. Technical Report 3000, INRIA, 1996.

....approach is simpler. Earlier work on operational equivalence for object calculi has been concerned with stateless objects: Gordon and Rees (1996) and Gordon (1997) characterise contextual equivalence exactly via forms of bisimilarity induced by the primitive operational semantics of objects; Sangiorgi (1996) and Huttel and Kleist (1996) induce approximations to contextual equivalence via translations of objects into the calculus; Andersen, Pedersen, Huttel, and Kleist (1997) characterise the bisimilarity of Gordon and Rees via a modal logic. The main influence on this section has been the literature ....

Sangiorgi, D. (1996). An interpretation of typed objects into typed - calculus. In FOOL 3, New Brunswick.

....Java or Modula 3 threads and synchronization of method calls. Previously, two different approaches have been taken to study concurrent objects. The first has been to encode objects within a concurrent calculus (examples include Honda and Tokoro (1991) Pierce and Turner (1995) Walker (1995) and Sangiorgi (1996) ) The second has been to extend a concurrent calculus with primitive objects. Examples of this approach are Di Blasio and Fisher (1996) and Dal Zilio (1998) The guiding principle behind the design of our calculus is to preserve the notion of returning a value, so as to retain the ....

.... Chan s A :lA, we may use subsumption to derive: nil : A newChan s : lA ; nil : A newChan a : lA To further refine usage of these channel types we define a type of writeonly channels, A = write : A A] and a type of read only channels, #A = read : A] as in the work of Pierce and Sangiorgi (1996). The inclusions lA : A and lA :#A are part of the definition of Pierce and Sangiorgi s system but are derivable in ours. 102 6.2 A Single Threaded Fragment In this section, we adapt the type system from Section 5.1 to identity a deterministic single threaded fragment of concV, and show that ....

Sangiorgi, D. (1996). An interpretation of typed objects into typed - calculus. In FOOL 3, New Brunswick.

....more complex cases. Many authors observe that inheritance and synchronization then often conflict [14] In contrast, process calculi provide a simpler, finer grain parallelism, and this formal simplicity is appealing for a core calculus of objects. Several works encode objects in process calculi [20, 19, 12, 7] or, vice versa, supplement objects Microsoft Research y Dipartimento di Scienze dell Informazione, Universit a di Bologna, Mura Anteo Zamboni 7, 40127 Bologna, Italy z INRIA Rocquencourt, BP 105, 78153 Le Chesnay Cedex France. with concurrent primitives [15, 4, 11] In these works the ....

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Information and Computation, 143(1):34--73, 1998.

....processes are given in a first order type system with recursion and subtyping. The expressiveness of our calculus is demonstrated by an interpretation of Abadi and Cardelli s typed functional calculus of objects: Ob 1 : 2] that preserves subtyping. This is an expected result, since Sangiorgi [24] has already given a translation from Ob 1 : to the calculus, but both the encoding and the type system used are very different. In particular, in our encoding, a method update does not create a new object but is rather modeled as a change of state . Moreover, the operational correctness of our ....

....model multiple interactive objects. In the world of concurrency, Jones [18] and Walker [27] have used the calculus for translating parallel object oriented languages and for proving the validity of certain program transformations. But the source languages studied are untyped and rather simple. In [24], Sangiorgi gives the first interpretation of the typed Abadi Cardelli s calculus with subtyping in , and in [19] the authors give an interpretation of the imperative object calculus. There are also some works on the definition of concurrent calculus of objects obtained by extending sequential ....

Davide Sangiorgi. An interpretation of typed objects into typed -calculus. Technical Report 3000, INRIA, 1996.

....order to dene some methods for checking bisimilarities between processes. These techniques have been introduced as meta level tools for proving bisimulation relations [SM92, San95] and to our knowledge have only been used in papers about the theory of calculus, to prove bisimilarity laws (e.g. [BS98, San96a]) The idea behind the up to techniques is to reduce the size of the relation one has to exhibit to establish a bisimilarity property, by providing syntactical tools to manipulate pairs of processes before checking that these pairs belong to the relation. For example, the classical proof of ....

D. Sangiorgi. An interpretation of typed objects into typed - calculus. Technical Report RR-3000, INRIA, 1996. to appear in Information and Computation.

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D. Sangiorgi. An interpretation of typed objects into typed #-calculus. Information and Computation, 143(1), 1998.

....it would be dicult to prove behavioural properties of IOC from this interpretation, because very little is known of the theory of the target imperative calculus. Some previous studies of encodings of imperative or OOLs into process calculi, namely [16, Chapter 8] 27] 11] 29, 14] and [24, 10], are an important basis for our work. We brie y comment on the di erences. Milner [16, Chapter 8] showed how to translate a small imperative language into CCS. Vaandrager [27] Jones [11] and Walker, Liu and Philippou [29, 14, 20] have gone further, by translating parallel object oriented ....

....otherwise many useful program equalities are lost and the semantics cannot be used to validate the typing rules of the language. By contrast, types play a central role in our interpretation. For this reason, our interpretation of objects is di erent from those in the above mentioned works. In [10, 24], interpretations of, respectively, untyped and typed FOC into the calculus are given. No use is made of the calculus interpretation for for validating behavioural properties of the source Object Calculus. The syntax of FOC and IOC are similar, but their operational semantics are very ....

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D. Sangiorgi. An interpretation of typed objects into typed -calculus. Technical Report RR-3000, INRIA | Sophia Antipolis, 1996.

....placeholder for) the result of the call. In the function declaration (2) z is receptive; in the function call (3) x is linear receptive. Similar combinations of linear and receptiveness occur in the coding of higher order communications in [Tho93, San92] and of Object Oriented languages in [Wal95, Jon93, San96a]. Typically, receptiveness occurs in the modelling of resources which are private to one or more client processes (above, the resource is a function) A discipline similar to receptiveness is presently used in the compiler of Pict [PT97] to allow optimisations of the code implementing ....

.... components P 1 and P 2 ; splitting of the typing is usual in type systems which forbid autoconcurrency on names [Hon96, KPT96, Ama97a] Matching is allowed on plain names, but not on receptive names; this is typical of type systems where the input and output capabilities on names are separate [PS96, San96a]. In rule T sum, we do not allow choice on inputs at receptive names (this constraint can be relaxed but it would complicate some of our theorems) Lemma 3.1 (unicity of typing) If Delta; Gamma L P and Delta 0 ; Gamma 0 L P then Delta = Delta 0 and Gamma = Gamma 0 . Lemma 3.2 ....

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D. Sangiorgi. An interpretation of typed objects into typed -calculus. Technical Report RR-3000, INRIA-Sophia Antipolis, 1996.

....to ours for receptiveness. 19] uses a type system where types have a graph structure to prove the full abstraction of an encoding of the polyadic calculus into the monadic calculus. Graphs allow expressing sophisticated communication protocols but introduce some complications in the typing. [14] uses a type system with input output modalities and variant types to guarantee the adequacy of a translation of a typed object oriented calculus into the calculus. 11] studies the constraints imposed by parametric polymorphism. Some of the ideas in this paper should be useful to develop ....

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Technical Report RR-3000, INRIA-Sophia Antipolis, 1996.

....it would be difficult to prove behavioural properties of IOC from this interpretation, because very little is known of the theory of the target imperative calculus. Some previous studies of encodings of imperative or OOLs into process calculi, namely [16, Chapter 8] 27] 11] 29, 14] and [24, 10], are an important basis for our work. We briefly comment on the differences. Milner [16, Chapter 8] showed how to translate a small imperative language into CCS. Vaandrager [27] Jones [11] and Walker, Liu and Philippou [29, 14, 20] have gone further, by translating parallel object oriented ....

....otherwise many useful program equalities are lost and the semantics cannot be used to validate the typing rules of the language. By contrast, types play a central role in our interpretation. For this reason, our interpretation of objects is different from those in the above mentioned works. In [10, 24], interpretations of, respectively, untyped and typed FOC into the calculus are given. No use is made of the calculus interpretation for for validating behavioural properties of the source Object Calculus. The syntax of FOC and IOC are similar, but their operational semantics are very different ....

[Article contains additional citation context not shown here]

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Technical Report RR-3000, INRIA --- Sophia Antipolis, 1996.

....in Section 1 where name b is the location of the boolean True and False. In the translation of typed lambda calculi, the type of a lambda term becomes the type of its location name. Such correspondences on types can be established when translating functional, objectoriented, imperative languages [PS93, Kob98, San98a, RS99] (in the case of imperative languages, processes play the role of commands; as the processes of the pi calculus, so the commands of imperative languages have all the same type) San98b] is a survey paper on the representation of functions (typed and untyped) as processes. A process model that, ....

....lambda calculus into the pi calculus allowed us to prove that the encoding preserved beta reduction, which is not true in the untyped case. I O modalities, together with variant types, have also been used to prove the adequacy of a translation of a typed object oriented language into calculus [San98a]. One difference between the way capabilities are restricted by polymorphism and by I O modalities is that, with the latter, capabilities that are lost can never be recovered. By contrast, in the polymorphic system the capabilities on a channel can increase and decrease: for instance, we may pass ....

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Information and Computation, 143(1):34--73, 1998.

No context found.

Sangiorgi, D. (1996). An interpretation of typed objects into typed - calculus. In FOOL 3, New Brunswick.

No context found.

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Information and Computation, 143(1):3473, May 1998.

No context found.

D. Sangiorgi. An interpretation of typed objects into typed -calculus. Information and Computation, 143(1):34-73, 1998.

No context found.

D. Sangiorgi. An interpretation of typed objects into typed -calculus. TR 3000, INRIA, 1996.

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