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Mixin modules are proposed as a new construct for module languages, allowing recursive definitions to span module boundaries. Mixin modules are proposed specifically for the Standard ML language. Several applications are described, including the resolution of cycles in module import dependency graphs, as well as functionality related to Haskell type classes and CLOS generic functions, though without any complications to the core language semantics. Mixin modules require no changes to the core ML type system, and only a very minor change to its run-time semantics. A type system and reduction semantics are provided, and the former is verified to be sound relative to the latter.

Abstract. This paper considers the effect of untyped attackers inside a distributed system where security is enforced by the type system. In previous work we introduced the Key-Based Decentralised Label Model for distributed access control. It combines a weak form of information flow control with cryptographic type casts to allow data to be sent over insecure channels. We present our model of untyped attackers in a simplified version of this calculus, which we call mini-KDLM. We use three sets of type rules. The first set is for honest principals. The second set is for attackers; these rules require that only communication channels can be used to communicate and express our correctness conditions. The third set of type rules are used to type processes that have become corrupted by the attackers. We show that the untyped attackers can leak their own data and disrupt the communication of any principals that place direct trust in an attacker, but no matter what the attackers try, they cannot obtain data that does not include an attacker in its access control policy.

An analysis is provided for Java programs that reverse engineers pa rameterizcd types into existing Java code. This analysis propagates precise type information about the contents of container objects. As an application, the analysis can be used to justify the safe removal of downcasts that are guaranteed to succeed. Another application is in automatically reverse engineering parametcrized types into existing Java libraries, so that they can be used in Java dialects with parameterized types.