Parallel Implementation through Object Graph Rewriting

Aldwych is proposed as the foundation of a general purpose language for parallel applications. It has aspects variously of concurrent, functional, logic and object-oriented languages, and may also interface with existing systems like a coordination language, yet it forms an integrated whole. It is intended to be applicable both for small-scale parallel programming, and for large-scale open systems Keywords: Concurrency, actors, multi-paradigm languages, coordination, open systems. 1. Introduction The language Linda [Gele 85] was launched as the underdog, competing against sophisticated approaches to parallel programming [Ca & Ge 89], but has triumphed over those approaches it then saw as its competitors, to the point where it is now seen as the generic model for "co-ordination languages" [Ci & Ha 96]. As its authors note [Ge & Ca 92] one of the main reasons for this is that Linda provided a simple "glue" that could be used to combine systems written in languages ...

Proceedings of the 26nd 2014 International Symposium on Implementation and Application of Functional Languages - IFL '14, 2014

Purely functional programming languages have proven to be an attractive option for implementing parallel applications. The lack of mutable state eliminates the possibility for race conditions, which relieves programmers of reasoning about the exponential interleavings of threads and nondeterministic behavior. Unfortunately, there are applications that by making use of shared state can achieve significant constant factor speedups compared to their purely functional counterparts. IVars have been proposed as a possible solution, allowing threads to share information via write-once references, while preserving a deterministic semantics. However, in the presence of speculative parallelism (cancelation), this determinism guarantee is lost. In this work we show how to go about combining these two concepts by proposing a dynamic rollback mechanism for enforcing determinism. We have formalized the semantics of a parallel functional language extended with IVars, speculative parallelism, and our proposed rollback mechanism using the Coq proof assistant, and have proven that it preserves determinism. Additionally, we describe a preliminary implementation in the context of the Manticore project, and give some initial performance results. 1 exception E 2 val i = IVar.new() 3 val _ = (|raise E, IVar.put(i, 10)|) 4 handle E => ((), ()) 5 val x = IVar.get i

Sigplan Notices, 1992

We describe an approach to implementing a wide-range of concurrency paradigms in high-level (symbolic) programming languages. The focus of our discussion is sting, a dialect of Scheme, that supports lightweight threads of control and virtual processors as rst-class objects. Given the signi cant degree to which the behavior of these objects may be customized, we can easily express a variety of concurrency paradigms and linguistic structures within a common framework without loss of e ciency. Unlike parallel systems that rely on operating system services for managing concurrency, sting implements concurrency management entirely in terms of Scheme objects and procedures. It, therefore, permits users to optimize the runtime behavior of their applications without requiring knowledge of the underlying runtime system. This paper concentrates on (a) the implications of the design for building asynchronous concurrency structures, (b) organizing large-scale concurrent computations, and (c) implementing robust programming environments for symbolic computing.

In this paper we present an operational semantics for concurrent interactive process es in the purely functional programming language Clean. An interactive process is in essence a state transition system which apart from its logical state can also access the state of the file system, do highlevel Graphical User I/O, and do inter-process communication via synchronous and asynchronous message passing and data sharing. Inter-process communication is type-safe and polymorphic. The semantics of the system is based on earlier work on the Interleaved Event I/O system. In this paper we identify limitations of the interleaved model in the context of concurrent processes and propose a new process semantics that does allow a concurrent implementation. The method basically intro duces a Remote Procedure Call communication scheme and demonstrates how to apply this scheme to obtain a concurrent process semantics. The resulting system is the Concur rent Event I/O system . The operational semantics is given in Clean itself. As a result the concurrency system is completely func tional because the construction is done within the pure functional framework.

HAL (Le Centre pour la Communication Scientifique Directe), 2016

Choreographic Programming is an emerging paradigm for correct-by-construction concurrent programming. However, its applicability is limited by the current lack of support for reusable procedures. We propose Procedural Choreographies (PC), a choreographic language model with full procedural abstraction. PC includes unbounded process creation and name mobility, yielding a powerful framework for writing correct concurrent algorithms that can be compiled into a process calculus. This increased expressivity requires a typing discipline to ensure that processes are properly connected when enacting procedures.

Electronic Notes in Theoretical Computer Science, 2002

This paper presents the formal specification of an abstract machine for the M-calculus, a new distributed process calculus. The M-calculus can be understood as an extension of the Join calculus that realizes an original combination of the following features: programmable localities, higher-order functions and processes, process mobility, and dynamic binding. Our abstract machine covers these different features and presents a modular structure that clearly separates the sequential (functional) evaluation mechanism from the execution core, and the latter from basic marshalling, location and routing mechanisms. c 2002 Published by Elsevier Science B. V. GERMAIN, LACOSTE, AND STEFANI

SOFSEM'96: Theory and Practice of Informatics, 1996

Proceedings Sixth IEEE International Conference on Engineering of Complex Computer Systems. ICECCS 2000

In this paper we present the ReSpecTX language, toolchain, and standard library as a first step of a path aimed at closing the gap between coordination languages-mostly a prerogative of the academic realm until now-and their industrial counterparts. Since the limited adoption of coordination languages within the industrial realm is also due to the lack of suitable toolchains and libraries of reusable mechanisms, ReSpecTX equips a core coordination language (ReSpecT) with tools and features commonly found in mainstream programming languages. In particular, ReSpecTX makes it possible to provide a reference library of reusable and composable interaction patterns.

1992

ACM SIGPLAN Notices, 2004

Recent functional logic languages such as Curry and Toy combine lazy functional programming with logic programming features including logic variables, non-determinism, unification, narrowing, fair search, concurrency, and residuation. In this paper, we show how to extend a conventional interpreter for a lazy functional language to handle these features by adding support for reference cells, process-like and thread-like concurrency mechanisms, and a novel form of multi-versioned store. Our interpretation scheme is practical, and can be easily extended to perform compilation. The language specified by our interpreter is designed so that programs are deterministic in a novel and useful sense.