Gerard Berry and Gerard Boudol. The chemical abstract machine. In Proceedings of the ACM Symposium on Principles of Programming Languages, pages 81--94. ACM, January 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....do periodic stuff after (0.1 seconds) controller It is important to note that the n execution of this action will have terminated before the (n 1) execution starts. Execution Model The model of concurrent execution used by Timber is based on the idea of the Chemical Abstract Machine [4]. The state of an executing program is envisioned as a soup of molecules. Sometimes these molecules react together, becoming absorbed and producing new molecules as a result. There are two kinds of molecules in the Timber soup : objects and messages. Objects. Objects are always named. The ....

Gerard Berry and Gerard Boudol. The Chemical Abstract Machine. In Seventeenth annual ACM symposium on Principles of programming languages, 1990, San Francisco, CA, USA: ACM Press, .

....fi Figure 2: Structural congruence laws of Calculus A. expressions with respect to an equivalence relation called structural congruence. This setup is familiar in the theory of term rewriting [8] and has been applied to the semantics of concurrent programming in the Chemical Abstract Machine [3] and the Calculus [21] A binary relation j on the expressions of Calculus A is called a congruence if it satisfies the structural congruence laws in Figure 2. Proposition 3.1 The relation E j=j Delta F is a congruence. We define the structural congruence E j F of Calculus A to be the ....

....of the quotient that structural congruence imposes on the set of expressions. The laws for conjunction make conjunction into an operator building multisets of nonconjunctive expressions, where plays the role of the empty multiset. To use the metaphor of the Chemical Abstract Machine [3], conjunction creates the chemical solution in which concurrent computation can take place. The Quantifier Mobility Law SQM and the Renaming Law ensure that quantification does not hinder the flow of the chemical solution. With the congruence laws mentioned so far we can rewrite every expression ....

G'erard Berry and G'erard Boudol. The chemical abstract machine. In Proceedings of the 17th ACM Conference on Principles of Programming Languages, pages 81--94, San Francisco, CA, January 1990.

....does not wish to move, it may spawn a new thread which splits from the agent and then performs the desired move communication. Information thus acquired may be returned to the primary agent later via communication. We discuss this further in Example 3.4 of Section 3. The structural equivalence [4, 22], defined in Figure 3, relates closed systems (N M ) The purpose of the structural equivalence is to abstract from the static structure of terms, i.e. from the irrelevant details of the syntactic relation between composition (P j Q ) restriction ( ne)P ) and location ( JPK) The structural ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Conference Record of the ACM Symposium on Principles of Programming Languages, pages 81--94, San Francisco, January 1990. ACM Press. 46 HENNESSY AND RIELY

....functional nets as reduction systems. There is in each case only a single rewrite rule, which is similar to the # reduction rule of # calculus, thus closely matching intuitions of functional programming. By contrast, the original treatment of join calculus is based on a chemical abstract machine[BB90] a concept well established in concurrency theory. The two versions of join calculus complement each other and are (modulo some minor syntactical details) equivalent. 5.1 Purely Functional Calculus Figure 4 presents the subset of join calculus which can express purely functional programs. The ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Proc. 17th ACM Symposium on Principles of Programming Languages, pages 81--94, January 1990.

....defined. Processes in C (entities) can use Unix sockets (media) to coordinate. The laws of this model would clearly be laws that govern communication via sockets. Other coordination models include: GAMMA (General Abstract Model for Multiset Manipulation) BL90] CHAM (Chemical Abstract Machine) BB90] IAM (Interaction Abstract Machine) ACP93] LO (Linear Objects) AP92] Manifold [AR93] and Actors [Agh86] Although all the problems of garbage collection and distributed I O also exist in these models this thesis concentrates on the variations of the LINDA model [Gel85] 2.1.1 The LINDA ....

Gerard Berry and Gerard Boudol. The Chemical Abstract Machine. In ACM, editor, Proceedings of the seventeenth annual ACM symposium on Principles of programming languages, pages 81--94, New York, NY, USA, 1990. ACM Press.

....does not wish to move, it may spawn a new thread which splits from the agent and then performs the desired move communication. Information thus acquired may be returned to the primary agent later via communication. We discuss this further in Example 4 of Section 3. The structural equivalence [4, 20], defined in Table 3, relates closed systems (P n Q) The purpose of the structural equivalence is to abstract from the static structure of terms, i.e. from the irrelevant details of the syntactic relation between composition (p E q) restriction ( G ne I p) and location (06C p D ) The ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Conference Record of the ACM Symposium on Principles of Programming Languages, pages 81--94, San Francisco, January 1990. ACM Press.

....of a global environment where tuples and processes live together, and agents react to the environment according to some simple rules; for instance, Brownian motion. This analogy has inspired Berry and Boudol to the definition of a concurrent computing model called the Chemical Abstract Machine [4]. This model seems extremely promising for the class of languages listed in the introduction, and in particular for Linda. 4.1 The Chemical Abstract Machine Sequential abstract machines are very useful tools to study sequential programming languages, providing a unified framework to discuss both ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Proc. 17 th ACM Conf. on Principles of Programming Languages, pages 81--94, 1990.

....does not wish to move, it may spawn a new thread which splits from the agent and then performs the desired move communication. Information thus acquired may be returned to the primary agent later via communication. We discuss this further in Example 4 of Section 3. The structural equivalence [4, 20], defined in Table 3, relates closed systems (P j Q) The purpose of the structural equivalence is to abstract from the static structure of terms, i.e. from the irrelevant details of the syntactic relation between composition (p j q) restriction ( ne)p) and location ( JpK) The structural ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Conference Record of the ACM Symposium on Principles of Programming Languages, pages 81--94, San Francisco, January 1990. ACM Press.

....does not wish to move, it may spawn a new thread which splits from the agent and then performs the desired move communication. Information thus acquired may be returned to the primary agent later via communication. We discuss this further in Example 4 of Section 3. The structural equivalence [4, 20], defined in Table 3, relates closed systems (P Q) The purpose of the structural equivalence is to abstract from the static structure of terms, i.e. from the irrelevant details of the syntactic relation between composition (p j q) restriction ( ne)p) and location ( JpK) The structural ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Conference Record of the ACM Symposium on Principles of Programming Languages, pages 81--94, San Francisco, January 1990. ACM Press.

....areas [Bou89, Ode95a, Bou97] As such it seems well suited to take over from lambda calculus as a generally agreed upon foundation of programming. Join calculus has traditionally been introduced as a process calculus, and its operational semantics has been explained as a chemical abstract machine [BB90, FG96] We show in this paper that join calculus can be regarded equivalently as a concurrent version of lambda calculus, with an operational semantics expressed as a reduction system. Our presentation of join calculus has a single reduction rule, similar to # V reduction in the call by value ....

Gerard Berry and Gerard Boudol. The chemical abstract machine. In Proc. 17th ACM Symposium on Principles of Programming Languages, pages 81--94, January 1990.

....the messages are elementary processes that can be sent without any sequencing constraint. Furthermore, names may be restricted, making them private in the context of an agent. 2 These two concepts are sufficient to encode the synchronous communication of the calculus. Chemical Abstract Machine [37]: The chemical abstract machine is a semantic framework based on the chemical metaphor used in the Gamma language of Banatre and Le Metayer. States of a machine are understood as chemical solutions where molecules may interact according to reaction rules. It is possible to dynamically encapsulate ....

G. Boudol and G. Berry, "The chemical abstract machine," Theoretical Computer Science, vol. 96, pp. 217--248, 1992.

....some detail in my thesis [Sar89] and we shall not re make that case here. The purpose of this paper is to explore the higher order analog of the cc languages. We are motivated in part by the obvious need to understand the interaction between concurrency and higher order calculi (see for example [Bou89, Tho90, MPW89, BB90]) in part by the need to understand at a more fundamental level the relationship between the cc programming framework, and Scott s conception of computation, and in part by the need to get a more powerful framework for computing with constraints than provided by the first order cc languages. For ....

Gerard Boudol and G. Berry. The Chemical Abstract Machine. In Proceedings of the 17th Annual ACM Symposium on Principles of Programming Languages, pages 81--94. ACM, 1990.

....class of computational phenomena. In particular, we will develop the concept of linear CCP, which we believe will provide a simple, elegant logical account of various distributed computation models such as the actors formalism of [89] the calculus of [131] the Chemical Abstract Machine of [22], the (intuitionistic) cc languages, and Shared Prolog. One of the primary areas of research in concurrency theory today is the study of higher order process calculii. We will examine higher order concurrent constraint programming languages, with special emphasis on developing higher order ....

Gerard Boudol and G. Berry. The Chemical Abstract Machine. In Proceedings of the 17th Annual ACM Symposium on Principles of Programming Languages, pages 81--94. ACM, 1990.

....as choosing one of the component of A B to verify the sequent within the context Gamma. Since computation is to search for a successful proof, the choice may be influenced by other formulae in Gamma (i.e. the environment) This corresponds to the external choice in concurrent programming [BG90]. Thus, don t care non determinism (committedchoice) for which the arrival nondeterminism is a special case, can be uniformly modelled in terms of additive conjunction. Communication between processes is realised by passing messages, as outlined in the following deduction: Gamma; B;A[t 1 =y] ....

Gerard Boudol and G.Berry. The chemical abstract machine. In Proc. of the 17th Annual ACM symposium on Principle of Programming Languages. ACM, 1990.

....as choicing one of the component of A B to verify the sequent within the context Gamma. Since computation is to search for a successful proof. The choice may be influenced by other formulae in Gamma (i.e. the environment) It corresponds to the external choice in concurrent programming [BG90] Thus, don t care non determinism (committed choice) in concurrent logic programming, where choice is generally made externally, can be uniformly modelled in terms of additive conjunction. Additive Disjunction for Fork: The left rule for additive disjunction Phi Gamma; A Delta Gamma; B ....

.... where the syntax of a receiver is defined as following: m 4 = x(t) singer receiver j m Omega m multiple receivers An intuitive description of the concurrent computation model underlying the calculus may be given following the approach of Berry and Boudol s chemical abstract machine (CHAM) BG90] where the concurrent components in a system are regarded as freely moving in the system and communicate when they come in contact. The state of a system is like a chemical solution in which floating molecules can interact with each other according to reaction rules. Within the calculus, ....

[Article contains additional citation context not shown here]

Gerard Boudol and G.Berry. The chemical abstract machine. In Proc. of the 17th Annual ACM symposium on Principle of Programming Languages. ACM, 1990.

....these ideas lead to the formula as agent interpretation of a larger class of logics. A subset of the formulas of the logic are viewed as computational agents. The left rules in a sequent style presentation of the logic are taken to specify the operational heating rules (in the style of [BB90]) which describe how complex agents may be decomposed into simpler agents, and the basic interactions betwen these agents. Thus, the operational derivability relation between configurations qua agents is related to the entailment relation between configurations qua logical formulas. In general, ....

Gerard Boudol and G. Berry. The Chemical Abstract Machine. In Proceedings of the 17th Annual ACM Symposium on Principles of ProgrammingLanguages, pages 81--94. ACM, 1990.

....multiple shared dataspaces and a more precise interaction protocol. ESP [3] instanciates PoliS and uses Prolog as sequential language. Another family of models merges the coordination mechanisms and the sequential language into a unique formalism, for instance the Chemical Abstract Machine [2] which considers programs as multiset transformations. In a concurrent object oriented framework, we can put forward the Maude language [8] which uses a rewriting logic and the COOLL language [4] that relies on a fragment of linear logic. However, the handling of object oriented principles in ....

G. Berry and G. Boudol. The Chemical Abstract Machine. In Sevententh Annual ACM Symposium on Principles of Programming Languages, pages 81--94, San Francisco, CA., January 1990.

....a process must have free names. The set Proc = fP j fv(P ) g is the set of closed processes. 4. 1 The Reaction Relation The reaction relation is a concise account of computation in the pi calculus introduced by Milner [Mil92] inspired by the Chemical Abstract Machine of Berry and Boudol [BB90]. One thinks of a process as consisting of a chemical solution of molecules waiting to react. A reaction step arises from the interaction of the adjacent molecules mhNi:P and m(x) Q, as follows: mhNi:P j m(x) Q P j Q[N=x] Just as one might stir a chemical solution to allow nonadjacent ....

G. Berry and G. Boudol. The chemical abstract machine. In Conference Record of the Seventeenth ACM Symposium on Principles of Programming Languages, pages 81--94, 1990.

....is written j ff . We also set fu(P ) def = fc(P ) fn(P ) Processes without free variables or free channels are called programs. 2.3. Operational Semantics. For the concise definition of the operational semantics of the language constructs, we introduce the structural equality j (cf. [5, 17]) which is the smallest congruence relation on processes including the following equations. 1. P j Q if P j ff Q. 2. P j inact j P , P j Q j Q j P , P j Q) j R j P j (Q j R) 3. u)inact j inact, uu)P j (u)P , uu 0 )P j (u 0 u)P , u)P j Q j (u) P j Q) if u 62 fu(Q) u)def D in P j def ....

....(b) Fact[b] j y = call b[x Gamma 1] in return[x y] Here and henceforth we write X( x k) P , or a sequence of such equations, for the declaration part of recursion, leaving the body part implicit. This example implements the standard recursive algorithm for the factorial function. y = call f[5] in P would give its client process. The communication patterns based on call return are easily representable by the combination of request accept and send receive. We first show the mapping of the caller. Below [ Delta] denotes the inductive mapping into the structuring primitives. x = call ....

G. Berry and G. Boudol. The chemical abstract machine. TCS, 96:217--248, 1992.

.... the whole system, into a typable local redex (hu ( Ri j uv 1 Delta Delta Delta v k ) the typing of which can be transformed, by a kind of cut elimination, into a typing of Rv 1 Delta Delta Delta v k ) This is not so easy, because typing is not compatible with chemical transformations [4], allowing the components of a parallel system to freely move. Related Work The idea of using trace languages as types is not new. For instance, Abramsky, Gay and Nagarajan [1] developed a semantic framework for types, namely interaction categories, based on this idea. Regular trace ....

....relation P P 0 , the main ingredient being message passing , that is the transformation of uz 1 Delta Delta Delta z n into Rz 1 Delta Delta Delta z n , where R is a resource found for u in the environment, either in a declaration or in a definition. The chemical metaphor (see [4]) would be perfect here, since we want to describe asynchronous computations, where no ordering is assumed on the messages for a given name. However, this style is difficult to maintain with typing purposes, therefore we use a more traditional style, with evaluation contexts. Nevertheless, we ....

G. Berry, G. Boudol, The chemical abstract machine, Theoretical Comput. Sci. 96 (1992) 217-248.

....that Reppy gives it in CML. As a result, we now have a semantics for the basic primitives of CML. Thus for semantic reasons we have arrived at the same result as Reppy, who used purely pragmatic reasoning. Our semantics has been influenced by Facile [GMP89] and the Chemical Abstract Machine [BB90]. However, we believe that our approach is simpler. For example, Facile can create a new process with either a behaviour expression or a fork function, and this results in some transitions being labelled with behaviour expressions. We avoid the need for such complex labels by eliminating behaviour ....

G. Berry and G. Boudol. The chemical abstract machine. In Proceedings of the Seventeenth ACM Symposium on Principles of Programming Languages, 1990.

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Gerard Berry and Gerard Boudol. The chemical abstract machine. In Proceedings of the ACM Symposium on Principles of Programming Languages, pages 81--94. ACM, January 1990.

No context found.

Gerard Berry and Grard Boudol. The chemical abstract machine. In Proceedings of the 17th ACM SIGPLAN-SIGACT symposium on Principles of programming laguages (POPL'90), pages 81--94. ACM Press, 1990.

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Gerard Berry and Gerard Boudol. The Chemical Abstract Machine. In ACM, editor, Proceedings of the seventeenth annual ACM symposium on Principles of programming languages, pages 81--94, New York, NY, USA, 1990. ACM Press.

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Berry, G., and Boudol, G. "The chemical abstract machine". Theor. Comp. Sci. 96 (1992), 217-248.

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