Christopher A. StoneAssociate Professor |
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This semester I am teaching CS 131 (Programming Languages) and co-teaching CS 5 (Introduction to Computer Science). My weekly schedule is available here.
My advising information for Joint CS/Math Majors and the companion advising information for CS majors should be useful to students and their advisors. Please let me know if there's anything I've left out that would be useful, or if there are any errors.
My CV and most of my publications are available on-line.
My research usually involves the theory or implementation of programming languages. I am particularly interested in type systems for functional and object-based languages.
More recently I've started the Observationally Cooperative Multithreading (OCM) project with Melissa O'Neill and several students. In traditional Cooperative Multithreading (CM), one thread runs at a time, and each thread runs until it explicitly yields the processor to the next thread. This permits a very simple and efficient programming model, because the lack of unexpected preemption means that that locks and the problems that go with them (not enough locks = race conditions, too many locks or locks acquired in the wrong order = deadlock) can be avoided.
The goal of OCM is to port the CM model to a multiprocessor. When threads are non-interacting, we run them simultanously without any change in behavior except for improved speed. Preliminary experiments with modified Lua interpreters (an optimistic-concurrency implementation using Software Transactional Memory and a pessimistic implementation internally using locks) are very encouraging.
Previously I have worked on a translator turning constructive-mathematics specifications into interface code for programmers. The system answers questions like, "What would a programmer need to implement in order to get a complete and correct implementation of the mathematical real numbers [or a compact metric space, or a space of smooth functions, ...]?" From an educational perspective, it also provides explanations (in terms a programmer can understand) of the non-classical distinctions that arise in constructive mathematics. For example, one can explain the difference between a finite set and a set that is not infinite, and why there is a "size" function only for the former.
I have also worked on types for object-based languages (languages that permit adding new fields or methods to individual objects at run-time) and on type checking algorithms for recursively-defined types.