Yann Radenac

Generalised multisets for chemical programming

Gamma is a programming model in which computation can be seen as chemical reactions between data represented as molecules floating in a chemical solution. This model can be formalised as associative, commutative, conditional rewritings of multisets where rewrite rules and multisets represent chemical reactions and solutions, respectively. In this article we generalise the notion of multiset used by Gamma and present applications through various programming examples. First, multisets are generalised to include rewrite rules, which become first-class citizens. This extension is formalised by the

Higher-Order chemical programming style

\gamma

A Generalized Higher-Order Chemical Computation Model

-calculus, which is a chemical model that summarises in a few rules the essence of higher-order chemical programming. By extending the

The Chemical Reaction Model Recent Developments and Prospects

\gamma

Chemical Specification of Autonomic Systems

-calculus with constants, operators, types and expressive patterns, we build a higher-order chemical programming language called HOCL. Finally, multisets are further generalised by allowing elements to have infinite and negative multiplicities. Semantics, implementation and applications of this extension are considered.

Programming Self-Organizing Systems with the Higher-Order Chemical Language.

The chemical reaction metaphor describes computation in terms of a chemical solution in which molecules interact freely according to reaction rules. Chemical solutions are represented by multisets of elements and reactions by rewrite rules which consume and produce new elements according to conditions. The chemical programming style allows to write many programs in a very elegant way. We go one step further by extending the model so that rewrite rules are themselves molecules. This higher-order extension leads to a programming style where the implementation of new features amounts to adding new active molecules in the solution representing the system. We illustrate this style by specifying an autonomic mail system with several self-managing properties.

Service Orchestration Using the Chemical Metaphor

Gamma is a programming model where computation is seen as chemical reactions between data represented as molecules floating in a chemical solution. Formally, this model is represented by the rewriting of a multiset where rewrite rules model the chemical reactions. Recently, we have proposed the @c-calculus, a higher-order extension, where the rewrite rules are first-class citizen. The work presented in this paper increases further the expressivity of the chemical model with generalized multisets: multiplicities of elements may be infinite and/or negative. Applications of these new notions are illustrated by some programming examples.

Principles of Chemical Programming

In 2001, we gave a survey of more than fifteen years of research on the chemical paradigm which had been a source of inspiration in many different research areas. The present article presents a digest of recent advances concerning the chemical reaction model. We focus to a large extent on: (1) upgrading the basic model to a higher order formalism allowing reactions to be part of solutions and to take part in reactions and (2) generalizing standard multisets to hybrid and infinite multisets, thus providing new forms of interactions between elements. These novelties, incorporated in the HOCL language (High Order Chemical Language), provide natural and elegant ways of expressing properties related to coordination and self-organization of systems. Finally, we present current research directions which strive to make the chemical reaction model effective particularly in the programming of large-scale, highly parallel applications such as Grids.