Latest documents http://publikationen.ub.uni-frankfurt.de/index/index/ Mon, 02 Jul 2012 16:16:23 +0100 Mon, 02 Jul 2012 16:16:23 +0100 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/24252 The calculus CHF models Concurrent Haskell extended by concurrent, implicit futures. It is a process calculus with concurrent threads, monadic concurrent evaluation, and includes a pure functional lambda-calculus which comprises data constructors, case-expressions, letrec-expressions, and Haskell’s seq. Futures can be implemented in Concurrent Haskell using the primitive unsafeInterleaveIO, which is available in most implementations of Haskell. Our main result is conservativity of CHF, that is, all equivalences of pure functional expressions are also valid in CHF. This implies that compiler optimizations and transformations from pure Haskell remain valid in Concurrent Haskell even if it is extended by futures. We also show that this is no longer valid if Concurrent Haskell is extended by the arbitrary use of unsafeInterleaveIO. David Sabel; Manfred Schmidt-Schauß workingpaper http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/24252 Tue, 07 Feb 2012 16:16:23 +0100 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/24253 We show how Sestoft’s abstract machine for lazy evaluation of purely functional programs can be extended to evaluate expressions of the calculus CHF – a process calculus that models Concurrent Haskell extended by imperative and implicit futures. The abstract machine is modularly constructed by first adding monadic IO-actions to the machine and then in a second step we add concurrency. Our main result is that the abstract machine coincides with the original operational semantics of CHF, w.r.t. may- and should-convergence. David Sabel workingpaper http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/24253 Tue, 07 Feb 2012 16:14:01 +0100 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2181 Reasoning about the correctness of program transformations requires a notion of program equivalence. We present an observational semantics for the concurrent lambda calculus with futures Lambda(fut), which formalizes the operational semantics of the programming language Alice ML. We show that natural program optimizations, as well as partial evaluation with respect to deterministic rules, are correct for Lambda(fut). This relies on a number of fundamental properties that we establish for our observational semantics. Joachim Niehren; David Sabel; Manfred Schmidt-Schauß; Jan Schwinghammer workingpaper http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2181 Mon, 30 Oct 2006 08:54:30 +0100