In the frame of the extended EU FP6-funded TYPES project, we are organizing an ad hoc "small workshop" on integration of effects into type-theoretic programming/reasoning. This is an informal event and attendance is not confined to people involved in TYPES. On the contrary, attendance and contributions from outside the TYPES consortium are most welcome. The invited speakers are Paul Levy and Aleksandar Nanevski. --- Call for contibutions and participation Workshop on Effects and Type Theory, EffTT Tallinn, Estonia, 13-14 December 2007 http://cs.ioc.ee/efftt/ a "small workshop" of the TYPES project Background The syntax and semantics of impurities of computation known as effects have been an important challenge for functional programming. Today, we tend to employ categorically inspired tools such as monads, Lavwere theories and arrows, but also more pragmatic approaches such as uniqueness typing. Effects are an issue also for type-theoretic programming and reasoning, where a number of aspects make them specifically interesting. First, we do not yet know what the best dependently typed generalizations of our simply typed tools are, although we hope they would reinforce the dual utility of type-theoretic calculi as programming languages and logics. Second, this duality specifically forces that pure computations must terminate, so even nontermination is an impurity and potentially an effect. Third, is it not likely that the type-theoretic glasses can help us see more clearly the particularities of external-world effects such as true destructively updatable state and true interactive input-output? Thus, this workshop is exactly about effects and type theory. Topics of interest include * all kinds of dependent generalizations of monads and more * type-theoretic language design for effects * type-theoretic effectful programming methodology * time, nontermination and type theory * state and type theory, including combinations of Hoare-like logics and type theory * interactive input-output and type theory * theories of external-world effects * type theory and concurrency * type-theoretic descriptions of physical systems * and any further topics about effects and type theory Invited speakers Our invited speakers are Paul Levy (Birmingham) and Aleksandar Nanevski (Microsoft Research, Cambridge). Contributing a talk The rest of the programme will be based on contributed talks and discussions. If you would like to contribute a talk, send a title and abstract to efftt(at)cs.ioc.ee by 21 November 2007. Organizers The workshop organizers are Thorsten Altenkirch, Marino Miculan and Tarmo Uustalu. Venue The workshop will take place in the building of the Estonian Academy of Sciences on Tallinn's Dome Hill. The workshop dates are during the Tallinn Christmas market and the Christmas Jazz festival of Jazzkaar. Participating To register, please drop an email to efftt(at)cs.ioc.ee as soon as possible, but not later than 21 November 2007. Attendance is not confined to people involved in the TYPES project; the workshop is open to anyone interested.