As many others, we too are developping a Massive Online Open Course or MOOC. This MOOC will teach recursive programming to beginners and will heavily use an already existing infrastructure for mechanical grading (Queinnec, 2010). This position paper discusses how these two components are combined in order to increase studentsâ?? involvement.

We introduce the Resource Aware Programming framework, which allows users to monitor the resources used by their programs and to programmatically express policies for the management of such resources. The framework is based on a notion of hierarchical groups, which act as resource containers for the computations they sponsor. Asynchronous notifications for resource exhaustion and for computation termination can be handled by arbitrary user code, which is also executed under the control of this hierarchical group structure. Resources are manipulated by the programmer using resource descriptors, whose operations are specified by a resource algebra. In this article, we overview the Resource Aware Programming framework and describe its semantics in the form of a language-independent abstract machine able to model both shared and distributed memory environments. Finally, we discuss a prototype implementation of the Resource Aware Programming framework in Java.

While developing the software of a browser-operated educational CD-ROM, we had to face a number of problems. This paper presents these problems and the solutions we found. Amusingly, most of our solutions rely on continuations. Are browsers and multimedia the future of continuations?Through their "Back" button or "Clone window" menu item, browsers have powerful abilities that force servers to take care of multiply and simultaneously answered questions. A comprehensive tool to apprehend these problems as well as to solve them is to view these abilities as operators acting on the continuations of the computation performed by servers.Thematical trails are provided to walk through the CD-ROM but do not prevent students to wander elsewhere. A trail may contain choices or quizzes so the rest of the trail should adapt to the walked part. We consider the trail as a computation and the position of the student as a continuation within that computation.Moreover this paper advocates a computation-centric view of servers (in opposition to the usual page-centric view) where interactions with users suspend the computation into continuations that may be later resumed. This approach is superior because the continuation reifies, automatically and without errors, the whole state of the computation.

Nowadays the Net is one of the most obvious driving forces. Yet, to consider it as one global store through which values and code may be shared is still immature. This paper suggests first-class environments as a means to achieve that goal in a multi-user Scheme framework. We propose two new special forms with a simple semantics. Our model allows precise control over environments (including extensible environments) and does not require (but does not prevent) reflective operations.

Distributed symbolic computations involve the existence of remote references allowing an object, local to a processor, to designate another object located on another processor. To reclaim inaccessible objects is the non trivial task of a distributed Garbage Collector (GC). We present in this paper a new distributed GC algorithm which (i) is fault-tolerant, (ii) is largely independent of how a processor garbage collects its own data space, (iii) does not need centralized control nor global stop-the-world synchronization, (iv) allows for multiple concurrent active GCs, (v) does not require to migrate objects from processor to processor and (vi) eventually reclaims all inaccessible objects including distributed cycles.

A partial continuation is a prefix of the computation that remains to be done.We propose in this paper a new operator which precisely controls which prefix is to be abstracted into a partial continuation.This operator is strongly related to the notion of dynamic extent which we denotationally characterize.Some programming examples are commented and we also show how to express previously proposed control operators.A suggested implementation is eventually discussed.