Fournet, C. and G. Gonthier, The re exive chemical abstract machine and the join-calculus, in: Proceedings of POPL '96, ACM, 1996, pp. 372-385.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....area calculus [4] a hierarchy of local areas is modeled and a same channel can have within its scope several disjoint local areas. The hierarchy, however, is prede ned, and explicit process mobility is not modeled in the local area calculus. Locations in the distributed Join calculus (DJoin) [5] are also organized as a tree. However, DJoin use transparent remote communication and migration based on simple names. Locations and process mobility in DJoin are mainly used for modeling distribution and failure. Another close work to T is the calculus with polyadic synchronization ) 2] ....

Fournet, C. and G. Gonthier, The re exive chemical abstract machine and the join-calculus, in: Proceedings of POPL '96, ACM, 1996, pp. 372-385.

....Sangiorgi has shown [21] that replication of general agents is not necessary, but it can be replaced by the guarded variant : P . This corresponds to using guarded recursion ( P def = P j : P ) In languages based on the 1 asynchronous communication such as Pict [20] or Join [3], it is relatively easy to see that it suces to have input guarded replication of the form x(y) P . These guarded variants of replication cannot be used in the solos calculus, where there are no pre x guarded terms present, but only solos. However, we can replace the unguarded unfolding of ....

C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In Proc. of POPL '96, pages 372-385. ACM, Jan. 1996.

....that objects can be de ned directly as sets of methods (procedures) acting over their state (represented as a set of logical variables) This representation is close to objects in TyCO if we view the state held in logical variables as template parameter bindings. Join implements the Join calculus [7, 8]. The JoCaml implementation integrates Join into the OCaml language. Join collapses the creation of new names, reception and replication into a single construct called a join pattern. Channels, both synchronous and asynchronous, expressions and processes are the basic abstractions. Programs are ....

C. Fournet and G. Gonthier. The Re exive Chemical Abstract Machine and the Join-Calculus. In Proceedings of the 23rd ACM Symposium on Principles of Programming Languages, pages 372-385. ACM, 1996.

....primitives [16, 3, 11] Those works promote a uni ed framework for reasoning about objects and processes, but they do not address the composition of object de nitions or its typechecking. In this work, we model concurrent objects in a simple process calculus a variant of the join calculus [7, 6], we design operators for behavioral and synchronization inheritance, and we give a type system that statically enforces basic safety properties. The join calculus is a simple name passing calculus, related to the pi calculus but with a functional avor. It is the core of a distributed ....

C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In Proceedings of POPL '96, pages 372-385, Jan. 1996.

.... the current paper, we present a calculus semantics for jeblik corresponding to the semantics proposed in [NHKM00] More precisely, our semantics uses an extension of Local [MS98, Mer00b] in short L , a variant of the asynchronous calculus [HT91, Bou92] where, similar to the Joincalculus [FG96] the recipients of a channel are local to the process that created the channel. The choice of L as the target language is not by accident: one of its fundamental laws is the forwarder law (cf. Lemma 2.15) ab = c) ac j c(x) bx) 3) where j represents parallel composition and replication ....

....mobile and travel according to a provably safe mobile state protocol from site to site, wherever they are needed or intend to go. 2 The typed local calculus Local [MS98, Mer00b] in short L , is a variant of the asynchronous calculus [HT91, Bou92] where, similar to the Join calculus [FG96] the recipients of a channel are local to the process that has created the channel. This is achieved by imposing the syntactic constraint that only the output capability of channels may be transmitted, i.e. the recipient of a channel may only use it in output actions. This property makes L ....

C. Fournet and G. Gonthier. The Re exive Chemical Abstract Machine and the Join-Calculus. In Proceedings of POPL '96, pages 372-385. ACM, Jan. 1996.

....give a notion of contextual equivalence for objects de ned in terms of may convergence on processes corresponding to the equivalence . More precisely, our semantics uses Local [MS98, Mer00] in short L , a variant of the asynchronous calculus [HT91, Bou92] where, like in Join calculus [FG96] the recipients of a channel are local to the process that has created the channel. We prove the correctness of surrogation for a wide class of jeblik programs. The proof is in two parts: an algebraic part and an iterative part. The algebraic part (Theorem 8.1) relates the core component of ....

....and travel according to a provably safe mobile state protocol from site to site, wherever they are needed or intend to go. 2 Local : An Object Oriented Calculus Local [MS98, Mer00] in short L , is a variant of the asynchronous calculus [HT91, Bou92] where, similar to the Join calculus [FG96] the recipients of a channel are local to the process that has created the channel. This is achieved by imposing the syntactic constraint that only the output capability of channels may be transmitted, i.e. the recipient of a channel may only use it in output actions. This property makes L ....

C. Fournet and G. Gonthier. The Re exive Chemical Abstract Machine and the Join-Calculus. In Proceedings of POPL '96, pages 372-385. ACM, Jan. 1996.

....strictly related ones to H Klaim are the distributed join calculus [15] and the ambient calculus [6] Both formalisms permit expressing active computational units which may move between localities of a structured net. The distributed join calculus has been obtained by extending the join calculus [14] (an asynchronous variant of the calculus [22] that combines the three operators for input, restriction and replication into a single operator: name de nition) with explicit locations and primitives for mobility. A net is a set of solutions (i.e. nodes) each one consisting of a distinct location ....

C. Fournet, G. Gonthier. The re exive chemical abstract machine and the join calculus. In Proc. of the ACM Symp. on Principles of Programming Languages, pp.372-385, 1996.

....JNW98] addressing Mobile IP, and [Mor99] which studies an infrastructure providing a similar abstraction to that of this paper. All involve more or less idealised models of algorithms rather than directly executable code. The latter includes encodings of choice [NP96] join communication [FG96] and authenticated communication [AFG00] all in terms of some code that in principle is executable. There is a trade o here: the idealised models can be expressed in a simpler formal framework, greatly simplifying correctness proofs, but they are further removed from implementation, increasing ....

....which studies an infrastructure providing a similar abstraction to that of this paper. All involve more or less idealised models of algorithms rather than directly executable code. The latter includes encodings of choice [NP96] join communication [FG96] and authenticated communication [AFG00], all in terms of some code that in principle is executable. There is a trade o here: the idealised models can be expressed in a simpler formal framework, greatly simplifying correctness proofs, but they are further removed from implementation, increasing the likelihood that important details ....

Cedric Fournet and Georges Gonthier. The re- exive chemical abstract machine and the joincalculus. In Proceedings of POPL '96 [ACM96], pages 372-385.

.... calculus [14] has provided a formal framework for most of the research on communication based concurrent systems. Several forms and extensions of the asynchronous calculus [11] have since been proposed to provide for more direct programming styles, and to improve eciency and expressiveness [3, 8, 21]. The calculus has also been used as a basis to reason about distributed computations. Introducing distribution, code mobility, and failure detection and recovery into computations is a fast growing research eld, with immediate applications in mobile computing, web languages, cryptography, to ....

....We feel that, the site organization should map the low level hardware architecture as closely as possible to allow an ecient implementation of the model. From a formal point of view our site organization is quite close to Distributed [16] and contrasts with the tree structure of Mobile Join [8] and the nested structure of Ambients [5] The model has two logical levels: processes and networks (cf. 2, 10, 16] Local computations happen at sites, as prescribed by the semantics of the base calculus. Remote computations occur between pre xed processes at di erent sites. In TyCO [21] such ....

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C. Fournet and G. Gonthier. The Re exive Chemical Abstract Machine and the Join-Calculus. In Proceedings of the 23rd ACM Symposium on Principles of Programming Languages, pages 372-385. ACM, 1996.

....in terms of cloning and aliasing. Due to lack of space, proofs are sketched or omitted; complete proofs are found in the full paper. 2 Local : An Object Oriented Calculus Local [12] in short L , is a variant of the asynchronous calculus [7] where, similar to the Join calculus [5], the recipients of a channel are local to the process that has created the channel. This is achieved by imposing the syntactic constraint that only the output capability of names may be transmitted, i.e. the recipient of a name may only use it in output actions. This property makes L ....

C. Fournet and G. Gonthier. The Re exive Chemical Abstract Machine and the join-calculus. In Proceedings of POPL '96, ACM, 1996.

....programs can use principal identities for security, for example in access control lists. The second bene t is more surprising: the treatment of principal identities allows a lighter, cheaper implementation, as explained below. Overview As source language, we adopt a variant of the join calculus [15, 14]. In addition to constructs for channel de nitions, parallel composition, and conditionals, which are part of the core join calculus, this variant also includes a syntactic category of principals and the following process forms: xha : v2 ; vn i is an authenticated message on channel x, ....

....join calculus; much of it is borrowed verbatim from a previous paper [3] This review does not cover the authentication constructs, which are the subject of the main body of the paper. The join calculus is a calculus of concurrent processes that communicate through named, one directional channels [15]. It can express functional and imperative constructs, and constitutes the core of a distributed programming language [17, 14] From a security perspective, we may say that the channels of the join calculus have a strong secrecy property: only the process that creates a channel can receive ....

Cedric Fournet and Georges Gonthier. The re exive chemical abstract machine and the join-calculus. In Proceedings of POPL '96, pages 372-385. ACM, January 1996.

....Despite the development of a large collection of design patterns [20] and of many concurrent languages [2, 24, 1] only monitors have gained widespread acceptance as programming constructs. An interesting new linguistic approach has emerged recently with Fournet and Gonthier s Join Calculus [9, 8], a process calculus well suited to direct implementation in a distributed setting. Other languages, such as JoCaml [6] and Funnel [23] combine similar ideas with the functional programming model. Here we propose an adaptation of Join Calculus ideas to an object oriented language that already has ....

C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In Proc. POPL'96, pages 372-385. ACM, January 1996.

....in 0 xhi def fxg xhi . yhi in xhi Now the process can input more messages on x, and also perform the two transitions below to consume the message on x and emit a message on y: def fxg xhi . yhi in xhi def fxg xhi . yhi in yhi fgyhi def fxg xhi . yhi in 0 We now extend the rcham of [14] with extrusions, intrusions, and explicit bookkeeping of extruded names. De nition 31 Open chemical solutions, ranged over by S; T ; are triples (D; S; A) written D S A, where D is a multiset of de nitions, S is a subset of the names de ned in D, and A is a multiset of open processes ....

C. Fournet and G. Gonthier. The re exive chemical abstract machine and the joincalculus. In Proceedings of POPL'96, pages 372-385. ACM, Jan. 1996.

....Cambridge, U.K. 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. 1 In this work, we model concurrent objects in a simple process calculus a variant of the join calculus [8, 7], we design operators for behavioral and synchronization inheritance, and we give a type system that statically enforces basic safety properties. The join calculus is a simple name passing calculus, related to the pi calculus but with a functional avor. It is the core of a distributed programming ....

....nitions, noted fn( are de ned according to these binders. A formal de nition of free names can be found in Figure 4. Terms are taken modulo renaming of bound names (or conversion) 2. 3 Chemical semantics The operational semantics is de ned in terms of a re exive chemical abstract machine [8]. Each rewrite rule applies to con gurations of objects and processes, called chemical solutions. A solution D P consists of a set 5 of named object de nitions D and of a multiset of processes P running in parallel. We write x:D for a named de nition in D, and always assume that there is at ....

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C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In Proceedings of POPL '96, pages 372-385, Jan. 1996.

....translation (theorem 3) 31 List of Figures 1 Translation from In Out ambient processes to the join calculus . 4 2 Additional clauses for the full translation . 5 3 Syntax for an ambient calculus extended with transient states . 9 4 Semantics for an ambient calculus extended with transient states . 9 5 Syntax for the ambient calculus . 19 6 Operational semantics for the ambient calculus . 19 7 Syntax for the distributed join calculus . ....

....from In Out ambient processes to the join calculus . 4 2 Additional clauses for the full translation . 5 3 Syntax for an ambient calculus extended with transient states . 9 4 Semantics for an ambient calculus extended with transient states . 9 5 Syntax for the ambient calculus . 19 6 Operational semantics for the ambient calculus . 19 7 Syntax for the distributed join calculus . 21 8 Operational semantics for the distributed join ....

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C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In POPL'96, pages 372-385. ACM, Jan. 1996.

....6 Communication. Ambient communication is implemented by supplementing every ambient manager with a rule DC that binds two channels snd and rcv and synchronizes message outputs and message requests. This encoding is much like the encoding of pi calculus channels into the join calculus (see [8]) Replication. Each replicated process P is coded using a standard recursive encoding of in nite loops in the join calculus. Open. Ambient processes may dissolve ambient boundaries using the open a capabilities. In contrast, join calculus names are statically bound to their de ning location, ....

C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In POPL '96, pages 372-385. ACM, Jan. 1996.

....primitives [17, 3, 12] Those works promote a uni ed framework for reasoning about objects and processes, but they do not address the composition of object de nitions or its typechecking. In this work, we model concurrent objects in a simple process calculus a variant of the join calculus [8, 7], we design operators for behavioral and synchronization inheritance, and we give a type system that statically enforces basic safety properties. The join calculus is a simple name passing calculus, related to the pi calculus but with a functional avor. It is the core of a distributed ....

....scope of z is every guarded process in D. Free names in processes and de nitions are de ned according to these binders. Terms are taken modulo renaming of bound names (or conversion) 4 2. 3 Chemical semantics The operational semantics is de ned in terms of a re exive chemical abstract machine [8]. Each rewrite rule applies to con gurations of objects and processes, called chemical solutions. A solution D P consists of a set of named object de nitions D and of a multiset of processes P running in parallel. We write x:D for a named de nition in D, and always assume that there is at most ....

[Article contains additional citation context not shown here]

C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In Proceedings of POPL '96, pages 372-385, Jan. 1996.

....implementation of concurrent calculi with message passing raises the problem of implementing communication channels, which nally reduces to the speci cation of channel managers. In order to re ect this need in the language itself, a new formalism has been recently introduced : the join calculus [2]. This calculus is similar to Milner s asynchronous calculus, except that the operations of restriction, reception and replication are all combined into a single receptor de nition. Such a combination yields better control over communication. In [2, 3] we relied on this locality property to ....

....been recently introduced : the join calculus [2] This calculus is similar to Milner s asynchronous calculus, except that the operations of restriction, reception and replication are all combined into a single receptor de nition. Such a combination yields better control over communication. In [2, 3], we relied on this locality property to model realistic distributed systems. In this paper, we propose a type system for the join calculus whose simplicity owes much to locality. The join calculus is quite expressive (a lot of examples may be found in [2, 3] and has been turned into a ....

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C. Fournet and G. Gonthier. The re exive chemical abstract machine and the join-calculus. In 23rd ACM Symposium on Principles of Programming Languages (POPL'96), 1996.

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