Static Safety for an Actor Dedicated Process Calculus by Abstract Interpretation

The actor model eases the definition of concurrent programs with non uniform behaviors. Static analysis of such a model was previously done in a data-flow oriented way, with type systems. This approach was based on constraint set resolution and was not able to deal with precise properties for communications of behaviors. We present here a new approach, control-flow oriented, based on the abstract interpretation framework, able to deal with communication of behaviors. Within our new analyses, we are able to verify most of the previous properties we observed as well as new ones, principally based on occurrence counting

Strategic polymorphism requires just two combinators!

In previous work, we introduced the notion of functional strategies: first-class generic functions that can traverse terms of any type while mixing uniform and type-specific behaviour. Functional strategies transpose the notion of term rewriting strategies (with coverage of traversal) to the functional programming paradigm. Meanwhile, a number of Haskell-based models and combinator suites were proposed to support generic programming with functional strategies. In the present paper, we provide a compact and matured reconstruction of functional strategies. We capture strategic polymorphism by just two primitive combinators. This is done without commitment to a specific functional language. We analyse the design space for implementational models of functional strategies. For completeness, we also provide an operational reference model for implementing functional strategies (in Haskell). We demonstrate the generality of our approach by reconstructing representative fragments of the Strafunski library for functional strategies.Comment: A preliminary version of this paper was presented at IFL 2002, and included in the informal preproceedings of the worksho

The Sketch of a Polymorphic Symphony

In previous work, we have introduced functional strategies, that is, first-class generic functions that can traverse into terms of any type while mixing uniform and type-specific behaviour. In the present paper, we give a detailed description of one particular Haskell-based model of functional strategies. This model is characterised as follows. Firstly, we employ first-class polymorphism as a form of second-order polymorphism as for the mere types of functional strategies. Secondly, we use an encoding scheme of run-time type case for mixing uniform and type-specific behaviour. Thirdly, we base all traversal on a fundamental combinator for folding over constructor applications. Using this model, we capture common strategic traversal schemes in a highly parameterised style. We study two original forms of parameterisation. Firstly, we design parameters for the specific control-flow, data-flow and traversal characteristics of more concrete traversal schemes. Secondly, we use overloading to postpone commitment to a specific type scheme of traversal. The resulting portfolio of traversal schemes can be regarded as a challenging benchmark for setups for typed generic programming. The way we develop the model and the suite of traversal schemes, it becomes clear that parameterised + typed strategic programming is best viewed as a potent combination of certain bits of parametric, intensional, polytypic, and ad-hoc polymorphism

Transitional labour markets: A new European employment strategy

Although it has become fashionable to reject full employment as a realistic objective for economic and social policy, there is one important reason to stick to this goal. Full employment always reflected the idea that all persons should have the right to earn a decent living through their own work. It is this connotation of social integration by full participation in the working life that makes full employment still powerful as a regulatory idea. However, the content of this goal deserves reconsideration. The model of continuous and dependent fulltime employment is no longer up to date, although it still implicitly underlies many institutional arrangements. This male breadwinner norm denies full employment participation to women on the one hand, and relieves men from full responsibility in the family life on the other hand. This paper suggests replacing this norm by the regulatory idea of transitional labour markets. -- Obwohl es Mode geworden ist, Vollbeschäftigung als ein realistisches Ziel für Wirtschafts- und Sozialpolitik zu verwerfen, gibt es einen wichtigen Grund, an diesem Ziel festzuhalten. Vollbeschäftigung reflektierte schon immer die Idee, daß alle Menschen das Recht haben sollten, einen menschenwürdigen Lebensunterhalt durch eigene Arbeit zu verdienen. Es ist diese Bedeutung der sozialen Integration durch volle Teilnahme am Erwerbsleben, die das Vollbeschäftigungsziel immer noch als eine wirkungsvolle regulative Idee erscheinen läßt. Dennoch bedarf ihr Inhalt einer Neubesinnung. Das Modell der kontinuierlichen und abhängigen Vollzeiterwerbstätigkeit ist längst nicht mehr zeitgemäß, obwohl es noch vielen institutionellen Arrangements als implizite Norm zugrunde liegt. Dieses die Männer sind die Ernährer'-Modell verweigert den Frauen einerseits die volle Beteiligung am Erwerbsleben und entlastet andererseits die Männer von jeglicher Verantwortung im Familienleben. Dieses Papier schlägt vor, diese Norm durch die regulative Idee der Übergangsarbeitsmärkte zu ersetzen.

Experiments in Clustering Homogeneous XML Documents to Validate an Existing Typology

This paper presents some experiments in clustering homogeneous XMLdocuments to validate an existing classification or more generally anorganisational structure. Our approach integrates techniques for extracting knowledge from documents with unsupervised classification (clustering) of documents. We focus on the feature selection used for representing documents and its impact on the emerging classification. We mix the selection of structured features with fine textual selection based on syntactic characteristics.We illustrate and evaluate this approach with a collection of Inria activity reports for the year 2003. The objective is to cluster projects into larger groups (Themes), based on the keywords or different chapters of these activity reports. We then compare the results of clustering using different feature selections, with the official theme structure used by Inria.Comment: (postprint); This version corrects a couple of errors in authors' names in the bibliograph

Introduction to the Literature On Programming Language Design

This is an introduction to the literature on programming language design and related topics. It is intended to cite the most important work, and to provide a place for students to start a literature search