In memory of Gilles Kahn

The essence of this paper stems from discussions that the first author (Jean-Pierre Banâtre) had with Gilles on topics related with programming in general and chemical programming in particular. Gilles liked the ideas behind the Gamma model and the closely related Berry and Boudol's CHAM as the basic principles are so simple and elegant. The last opportunity Jean-Pierre had to speak about these ideas to Gilles, was when he presented the LNCS volume devoted to the Unconventional Programming Paradigms workshop. The 10 minutes appointment (at that time, he was CEO of INRIA) lasted a long time. Gilles was fine and in good humour, as often, and he was clearly happy to talk about a subject he loved. He spoke a lot about λ-calculus, the reduction principle, the β-reduction… a really great souvenir!

Abstract

Originally, the chemical model of computation has been proposed as a simple and elegant parallel programming paradigm. Data is seen as “molecules” and computation as “chemical reactions”: if some molecules satisfy a predefined reaction condition, they are replaced by the “product” of the reaction. When no reaction is possible, a normal form is reached and the program terminates. In this paper, we describe classical coordination mechanisms and parallel programming models in the chemical setting. All these examples put forward the simplicity and expressivity of the chemical paradigm.