Yitzhak Mandelbaum and I have been thinking about language support for program migration. We submitted a short paper, Towards a core calculus for implicitly migration-capable applications, to PEPM’12 summarizing what we’ve done so far and the direction we’re headed. Here’s the abstract:

Mobile computational devices, like smartphones, tablets and laptops, have become a standard part of the computing landscape. Moreover, many users regularly interact with an assortment of devices, including mobile ones. Therefore, the ability to migrate UI-enabled applications is becoming increasingly important. We describe a design-pattern for applications to simplify support for user-session migration and provide an overview of a lambda calculus for which significant elements of the design pattern can be implemented automatically.

We’d appreciate any ideas, comments, or questions.

João Belo, Atsushi Igarashi, Benjamin Pierce, and I submitted a paper, Polymorphic Contracts, to ESOP’11. Here’s the abstract:

Manifest contracts track precise properties by refining types with predicates—e.g., {x:Int | x > 0} denotes the positive integers. Contracts and polymorphism make a natural combination: programmers can give abstract types strong contracts, precisely stating pre- and post-conditions while hiding implementation details—for example, an abstract type of stacks might specify that the pop operation has input type {x:α Stack | not (empty x)}. We formalize this combination by defining FH, a polymorphic calculus with manifest contracts, and establishing its fundamental properties, including type soundness and relational parametricity. Our development relies on a significant technical improvement over earlier presentations of contracts: instead of introducing a denotational model to break a problematic circularity between typing, subtyping, and evaluation, we develop the metatheory of contracts in a completely syntactic fashion, omitting subtyping from the core system and recovering it post facto as a derived property.