A Type System For Call-By-Name Exceptions

We present an extension of System F with call-by-name exceptions. The type system is enriched with two syntactic constructs: a union type for programs whose execution may raise an exception at top level, and a corruption type for programs that may raise an exception in any evaluation context (not necessarily at top level). We present the syntax and reduction rules of the system, as well as its typing and subtyping rules. We then study its properties, such as confluence. Finally, we construct a realizability model using orthogonality techniques, from which we deduce that well-typed programs are weakly normalizing and that the ones who have the type of natural numbers really compute a natural number, without raising exceptions.Comment: 25 page

Juppix: a Linux Live-CD for Undergraduate Students

Juppix is a Linux Live-CD with a comfortable programming environment for the Java, C and O’Caml programming languages that has been distributed to hundreds of undergaduate students at the University of Paris 7 over the last few years. We describe the lessons we learnt while compiling and distributing Juppix, and outline our future plans. 1 Background and motivation Undegraduate teaching of programming at the University of Paris 7 is mostly based on Unix. During the first year, we use the Java programming language with some locally-developed packages [7] and the Emacs editor, in the second year, we add C and PHP, and third year students get to enjoy O’Caml. While on campus, our students do have access to a few dozen reasonably configured machines running a system consisting of FreeBSD Unix and the KDE desktop. In periods of high affluence, such as just before a project deadline, our computer rooms tend to be overcrowded. Even in normal times, many students prefer to wor

Une approche de la détection statique d'exceptions non rattrapées en appel par nom

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Computation of Chromatic Polynomials Using Triangulations and Clique Trees

International audienceIn this paper, we present a new algorithm for computing the chromatic polynomial of a general graph G. Our method is based on the addition of edges and contraction of non-edges of G, the base case of the recursion being chordal graphs. The set of edges to be considered is taken from a triangulation of G. To achieve our goal, we use the properties of triangulations and clique-trees with respect to the previous operations, and guide our algorithm to efficiently divide the original problem. Furthermore, we give some lower bounds of the general complexity of our method, and provide experimental results for several families of graphs

Understanding the dynamics of JavaScript

Abstract We report on preliminary results on understanding the nature of JavaScript programs. Our investigation is motivated by the goal of de-veloping a type system for JavaScript programs. As a prelude, we decide to gain a better understanding of the dynamic behaviour of JavaScript programs. In particular we are interested in understanding how dynamic JavaScript programs are in the real world.