E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. van Leeuwen, and M. Rem, editors, PARLE '91: Parallel Architectures and Languages Europe, Volume II, volume 506 of Lecture Notes in Computer Science, pages 202--219. Springer, 1991.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....in Haskell: data List a = Nil Cons a (List a) declares a (polymorphic) type List a whose binary data constructor Cons evaluates the first argument (of type a) This is specified by using the symbol in the first argument of Cons. Other lazy functional languages, such as Clean [ENPS92, NSEP92, PE93] allow for more general annotations. Example 5 The following specification if : Bool a a a if True x y = x if False x y = y is an annotated definition of the function if which forces the evaluation of the first argument of each if call (see the mark in the type declaration of ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. Leeuwen, and M. Rem, editors, Proc. of Parallel Architectures and Languages Europe, PARLE'91, LNCS 506:202-219, Springer-Verlag, Berlin, 1992.

....of Mercury before type classes and existential types were introduced. In the following chapters, we present type classes and existential types as extensions of this type system. 26 Type Classes The type systems of modern functional languages such as Haskell [27] Gofer [46] and Concurrent Clean [76] have signi cant extensions to the Hindley Milner type system. Their most important extension is their support for constrained genericity through type classes. A type class speci es an interface consisting of one or more methods. A type can be declared to be a member of a type class by ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. Eekelen, and M. J. Plasmeijer. Concurrent Clean. In Proceedings of the Conference on Parallel Architectures and Languages Europe, pages 202-219, Eindhoven, The Netherlands, June 1991.

....compiler to ensure that the operational behaviour corresponds to the declarative view of the program as often as possible. The uniqueness components of modes are like type constraints (in the functional programming world, these same constraints are sometimes attached to the types see [110] or [75]) and so we needn t consider them in our translation. We use the mode constraints in the program to define a total ordering of the conjoined literals on the right hand side of a clause (i.e. the body of the clause) Because we wish to allow the programmer to retain as much control as possible ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In Proceedings of the Conference on Parallel Architectures and Languages Europe, pages 202--219, Eindhoven, The Netherlands, June 1991.

.... inference disciplines have been widely studied, in particular with intersection types, and some work has also been done for TRS alone, more precisely, for Curryfied TRS (CuTRS) 8] which are first order TRS with application, that correspond to the TRS underlying the programming language Clean [34]. The interactions between LC and TRS for type systems a la Curry, instead, has not been extensively investigated. They were first studied in [7] where CuTRS extended with abstraction and reduction were defined, together with a notion of intersection type assignment for both the LC and ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE '91, Parallel Architectures and Languages Europe, Eindhoven, The Netherlands, volume 506-II of Lecture Notes in Computer Science, pages 202--219. Springer-Verlag, 1991.

....the DAAD (Deutscher Akademischer Austauschdienst) 53 ular to impose early additional demand in favour of parallelism. Although the programmer controls the amount of potential parallelism with this approach, the actual parallelism remains under the control of the runtime system. Concurrent Clean [8] takes a similar approach providing low level annotations to start remote and locally interleaved evaluations. The latter can be used to introduce additional demand. Tremblay and Gao [11] also investigated possibilities to introduce additional demand: result data structures are traversed in a ....

E. Nocker, J. Smetsers, M. Eekelen, and M. J. Plasmeijer. Concurrent Clean. In PARLE '91, Parallel Architectures and Languages Europe, Volume I: Parallel Architectures and Algorithms, LNCS 505. Springer, 1991.

....set of processors. If the language is extended with a set of annotations , then the programmer can express this mapping directly. This section outlines the form of these annotations. Various proposals have been presented, including ParAlfl ( 10] 12] Caliban ( 5] 15] and Concurrent Clean ([16]) These systems are all similar in that the program is annotated to indicate how expressions should be mapped to a set of virtual processors. The compiler then maps the virtual processors to those actually available. In all cases, the annotations are declarative in nature and do not alter the ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, M.J. Plasmeijer, "Concurrent Clean," in LNCS, PARLE'91, Vol 2, pp. 202-19.

.... the model of functional programming as, for example, witnessed in [17] Ranging from languages that just support purely regular computations, such as Sisal [16] and SAC [30] over languages based on the idea of skeletons [13] such as [14] to control parallel languages, such as Concurrent Clean [26]. The one parallel language that is closest to Nepal in terms of the parallel programming model is certainly Nesl [5] which has been the starting point of our research. In essence, it has been our aim to take the novel functionality of Nesl and develop it to a point where it could be integrated ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE '91, number 505/506 in Lecture Notes in Computer Science, pages 202-220. Springer-Verlag, 1991.

....of an essential fragment of the Object I O library to demonstrate the feasibility. We take especial consideration for the relevant design choices. One particular design choice, how to handle state, results in two versions. 1 Introduction The pure, lazy, functional programming language Clean [8, 16, 20] o ers a sophisticated library for programmers to construct Graphical User Interfaces (GUI) on a high level of abstraction, the Object I O library. The uniqueness type system [22, 7] of Clean is the fundamental tool to allow safe and ecient Input Output. This has been taken advantage of in the ....

Nocker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M., eds., Proceedings of Parallel Architectures and Languages Europe, June, Eindhoven, The Netherlands. LNCS 506, Springer-Verlag, pp. 202-219.

....of efficiency and precision is claimed to be a recent implementation by Jensen et al. [JHR94] Their implementation of abstract interpretation using chaotic fixpoint iteration is implemented in C and has not yet been incorporated in any compiler. Another implementation has been given for Clean [NSvP91, PvE93] This implementation is based on abstract reduction [Noc93] It is also written in C. Unfortunately, it is hidden in the Clean compiler and, therefore, comparisons to other implementations are hardly possible. We have developed an adaptation of abstract reduction to Haskell and have made ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Ekelen, and M. J. Plasmeijer. Concurrent Clean. In Springer Verlag, editor, Proc of Parallel Architecture and Languages Europe (PARLE'91), number 505 in Lecture Notes in Computer Science, pages 202--219, 1991.

....is conveniently supported through a shared memory model where arbitrary expressions can be annotated for parallel execution. Many parallel implementations of functional languages based on annotations have been designed and implemented, for example, Parallel Haskell [45] Id [36] concurrent Clean [37], and Sisal [11] In the sequel we show that, for parallel symbolic computing on distributed memory machines, Orca holds an intermediate position between message passing systems and functional programmingsystems, both in terms of functionality and performance. We compare how the three approaches ....

E. G. J. M. H. N ocker, J. E. W. Smetsers, M. C. J. D . van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In E. H. L. Aarts, J. van Leeuwen, and M. Rem, editors, 3rd Parallel architectures and languages Europe (PARLE), LNCS 505/506, pages 202--220, Veldhoven, The Netherlands, June 1991. Springer-Verlag, Berlin.

....but essential fragment of the Object I O library to demonstrate the feasibility. We take especial consideration for the relevant design choices. One particular design choice, how to handle state, results in two versions. 1 Introduction The pure, lazy, functional programming language Clean [8, 14, 18] o ers a sophisticated library for programmers to construct Graphical User Interfaces (GUI) on a high level of abstraction, the Object I O library. The uniqueness type system [20, 7] of Clean is the fundamental tool to allow safe and ecient Input Output. This has been taken advantage of in the ....

Nocker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M., eds., Proceedings of Parallel Architectures and Languages Europe, June, Eindhoven, The Netherlands. LNCS 506, Springer-Verlag, pp. 202-219.

....of the fact that Clean is a strongly typed language. In this paper we show how the evaluation of interactive objects is implemented in the object I O library. The evaluation can be handled elegantly using lazy evaluation. 1 Introduction For many years the functional programming language Clean [7, 13, 14] enables programmers to create efficient, interactive applications that use Graphical User Interfaces (GUIs) This is done by means of an extensive library that has been developed in Clean. The first publicly available version was the 0.8 I O library [1, 2] Newer versions have emerged, ....

Nocker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M., eds., Proceedings of Parallel Architectures and Languages Europe, June, Eindhoven, The Netherlands. LNCS 506, Springer-Verlag, pp. 202-219.

....do destructive updates in a pure functional framework, plays a crucial role. Furthermore, the object I O system makes extensive use of new type system facilities, namely type constructor classes and existential types. 1 Introduction In the pure, lazy, functional programming language Clean [7] [18] [19] one can develop real world applications using a high level I O system, released as version 0.8 [2] 3] It is available for programmers in the form of a library. The major part of the library is written completely in Clean, and only a small part interfaces with the operating system. The ....

Nocker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M., eds., Proceedings of Parallel Architectures and Languages Europe, June, Eindhoven, The Netherlands. LNCS 506, Springer-Verlag, pp. 202-219.

....of research. Lambda calculus (or rather combinator systems) forms the underlying model for the functional programming language Miranda [22] term rewriting systems are used in the underlying model for the language OBJ [14] and term graph rewriting systems is the model for the language Clean [8, 17]. The lambda calculus, term rewriting systems and graph rewriting systems themselves are type free, whereas in programming the notion of types plays an important role. Type assignment to programs and objects is in fact a way of performing abstract interpretation that provides necessary ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE '91, Parallel Architectures and Languages Europe, Eindhoven, The Netherlands, volume 506-II of Lecture Notes in Computer Science, pages 202--219. Springer-Verlag, 1991.

.... The following definition in Haskell: data List a = Nil Cons a (List a) declares a type List whose binary data constructor Cons evaluates the first argument (note the symbol in the first argument of the data constructor Cons) 41 Other lazy functional languages, such as Clean [ENPS92, NSEP92, PE93] allow for more general annotations. Example 11.2 The following specification if : Bool a a a if True x y = x if False x y = y is an annotated definition of the function if which forces the evaluation of the first argument of each if call (see the mark in the type declaration ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. Leeuwen, and M. Rem, editors, Proc. of Parallel Architectures and Languages Europe, PARLE'91, LNCS 506:202-219, Springer-Verlag, Berlin, 1992.

....reduction techniques. Two Chapter 2 Related Work 20 such systems are Alfalfa and Buckwheat [Gol89, Gol88] which are parallel implementations for the functional language ALFL on a Distributed Memory Intel iPSC hypercube, and a Shared Memory Encore Multimax, respectively. Concurrent Clean [NSvEP91] is another example of a lazy higher order language that uses parallel graph reduction based on annotations supplied by the programmer. 2.3.3 Other Approaches There are several other approaches to data parallel programming based on functional languages. A few of these are briefly mentioned ....

E G J M H Nocker, J E W Smetsers, M C J D van Ekelen, and M J Plasmeijer. Concurrent Clean. In E H L Aarts, J van Leeuwen, and M Rem, editors, PARLE'91, number 506, Vol. 2 in LNCS, pages 202--219. Springer-Verlag, 1991.

....the operations one wishes to perform on these systems in some declarative way. One of the rst external interface problems a declarative language needs to tackle is that of input and ouput. IO has the property that it must be done sequentially, and cannot be undone. Monads[8] linear types[7] and unique modes[5] are popular techniques used to model this behaviour; they all provide sequencing and nality in a declarative fashion. Various techniques have been developed for coping with this problem in Mercury (which probably apply equally to other declarative languages) For some time ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. Eekelen, and M. J. Plasmeijer. Concurrent Clean. In Proceedings of the Conference on Parallel Architectures and Languages Europe, pages 202-219, Eindhoven, The Netherlands, June 1991.

.... are required) Type assignment disciplines have been widely studied in the context of the LC, and some work has also been done for TRS, more precisely, for Curryfied TRS (CuTRS) 6] which are first order TRS with application, that correspond to the TRS that underlie the programming language Clean [26]. The interactions between LC and TRS in the context of type assignment were first studied in [5] where CuTRS extended with abstraction and fi reduction were defined, together with a notion of intersection type assignment for both the LC and the TRS fragments. Partially supported by NATO ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In PARLE '91, LNCS 506-II, pages 202--219. Springer-Verlag, 1991.

....has given rise to the opinion that functional programming comes of age (Pountain (1994) The spreadsheet project of which the results are described in this paper was set out to gather evidence to support this opinion. In the lazy, functional graph rewriting language Clean (Brus et al. 1987) N cker et al. 1991), Plasmeijer van Eekelen (1994) uniqueness typing (Barendsen Smetsers (1993) which is based on the underlying graph rewriting model (Barendregt et al. 1987) Plasmeijer van Eekelen (1993) can be used to indicate that upon its evaluation a function will hold the only reference to a ....

Nöcker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. 1991. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M. (editors), Proceedings of Parallel Architectures and Languages Europe, June 1991, Eindhoven, The Netherlands. LNCS 506, pp. 202-219. SpringerVerlag.

....Term Graph Rewriting Systems (TGRS) 12] are topics of research. LC (or rather Combinator Systems) constitutes the underlying model for the functional programming language Miranda [37] TRS were used in the underlying model for the language OBJ [22] and TGRS were the model for the language Clean [13, 32]. For the implementation of a language, independent of the chosen implementation model, the notion of types plays an important role. Types are essential to obtain efficient machine code when compiling a program and are also used to make sure that the programmer has a clearer understanding of the ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE '91, Parallel Architectures and Languages Europe, Eindhoven, The Netherlands, volume 506-II of Lecture Notes in Computer Science, pages 202--219. SpringerVerlag, 1991.

....in the context of LC, and recently some work has also been done in the direction of TRS. In [2] a notion of type assignment for Curryfied TRS (CuTRS) has been developed. CuTRS are first order TRS with application and correspond directly to the TGRS that underlie the programming language Clean [27], restricted to the subsystem without sharing. In later papers [8, 7] an investigation was made on which of the important properties of the intersection type assignment system for LC are also provable for TRS. Although LC and TRS were often studied separately, recently a greater interest has ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE '91, Parallel Architectures and Languages Europe, Eindhoven, The Netherlands, volume 506-II of Lecture Notes in Computer Science, pages 202--219. Springer-Verlag, 1991.

....is simply a parallel higher order function, it is straightforward to write skeletons using strategies. Both the parMap function in Section 3.1 and the pipeline function in Section 4.4 are actually skeletons. A more elaborate divide and conquer skeleton, based on a Concurrent Clean function (Nocker et al. 1991) can be written and used as follows. divConq : a b) a (a Bool) b b b) a Bool) a (a,a) b divConq f arg threshold conquer divisible divide not (divisible arg) f arg otherwise = conquer left right using strategy where (lt,rt) divide arg left = ....

....and Glynn, 1989) This covered behavioural aspects such as data and process placement, as well as simple partitioning and sequencing. As a compromise between simplicity and expressibility, however, we will describe the well known set of annotations that have been provided for Concurrent Clean (Nocker et al. 1991). The basic Concurrent Clean annotation is e P f args, which sparks a task to evaluate f args to WHNF on some remote processor and continues execution of e locally. Before the task is exported its arguments, args, are reduced to NF. The equivalent strategy is rnf args seq (rwhnf (f args) ....

Nocker, E.G.J.M.H., Smetsers, J.E.W., van Eekelen, M.C.J.D., and Plasmeijer, M.J., "Concurrent Clean", Proc. PARLE '91, Springer Verlag LNCS 505/506, (1991), pp. 202-- 220.

....integration of the component transformations. ffl Compilers for high level languages use transformations to improve the performance of compiled code. Some functional language compilers have demonstrated remarkable performance improvements that can be attributed to their transformation technology [NSvEP91, Pey96, San95, BA97, AJ97] Transformations can be applied either to a source language program, to a de sugared form of a source language program or, in a compiler, to a translated program form targeted to a particular computer architecture. We are interested in architecture independent ....

E. G. J. M. H. Nocher, J. E. W. Smetsers, M. C. J. D. van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE'91, volume 505 of Lecture Notes in Computer Science, pages 202--219. Springer Verlag, 1991.

....example with a window containing a button and a number display. Whenever the button is pressed, the number is increased by one. The example is written in C using the popular toolkit Motif [25] 2 static int count = 0; static Widget display; static void SetDisplay(Widget display, int i) char s[10]; Arg wargs[1] sprintf(s, d , i) 2 The example has been somewhat stripped; the callback arguments and arguments for determining various widget attributes are omitted, and so is the conversion between C strings and Motif strings. XtSetArg(wargs[0] XmNlabelString, s) XtSetValues(display, ....

....single stream. Whereas the interactions and dialogues might be good for text based I O, we do not find them appropriate for dealing with the parallel nature of a GUI. 9. 3 Concurrent Clean input output Concurrent Clean is a lazy language, where parts of the program can be evaluated in parallel [10]. The type system is 10 The interactions are a generalization of Dwelly s Dialogue combinators, which have the same type on the input and output values. extended with so called unique types, which very much resemble linear types. In [12] objects of unique types are used to model different ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeyer. Concurrent clean. In Proceedings of the PARLE'91 Parallel Architectures and Languages Europe conference (LNCS 505), Eindhoven, June 1991.

....must describe both computation and coordination, i.e. what to compute, and how to arrange the computation in parallel. In adding coordination constructs, many parallel functional languages are able to preserve the referential transparency of the computation language [NAH93,BCH 93,FMS 95,NSvEP91] and [BLOMP97] so that standard equational reasoning techniques continue to be applicable to the values computed. Being able to reason about coordination is, however, dependent on the form its specification takes: for languages in which coordination is entirely implicit [NAH93,BCH 93,FMS ....

....continue to be applicable to the values computed. Being able to reason about coordination is, however, dependent on the form its specification takes: for languages in which coordination is entirely implicit [NAH93,BCH 93,FMS 95,MS95] or in which it is specified as annotations [KG89,NSvEP91] reasoning about the coordination at the language level is not possible. It is only for languages that make the specification of coordination explicit [BLOMP97,CGKL98,Hal98] and [MH95] that such reasoning is possible at the language level. Our language, Glasgow Parallel Haskell (GpH) THJ ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proc. PARLE '91 --- Parallel Architectures and Reduction Languages Europe, volume 505/506 of LNCS, pages 202--220. Springer Verlag, 1991.

....programming languages rather than just using toy languages. The language we are going to analyze is of higher order and has non strict semantics. This means that we will analyze a language similar to languages used as intermediate languages in compilers for Haskell [HAB 96] or Clean [NSvP91] The introduction of functions as arguments poses a new challenge: it is not quite clear how to define orderings on expressions which denote functions, i.e. to find an interpretation for functions which can be used for defining an ordering. However, arguments which denote functions can (and ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In Springer Verlag, editor, Proc of Parallel Architecture and Languages Europe (PARLE'91), number 505 in Lecture Notes in Computer Science, pages 202--219, 1991.

....functional languages on more general purpose machines [3, 4, 14] This indicates that an intermediate level of abstraction is desirable. In this paper, some examples will illustrate how Concurrent Clean a lazy, higher order functional language with a few low level constructs for parallelism [15, 17, 19] can be used to implement a range of high level skeletons. In contrast to Darlington [9] not only the meaning of each skeleton will be established by its functional language definition, but also its behaviour. Thus, we will use a lazy functional programming language with general mechanisms for ....

Nöcker E.G.J.M.H., Smetsers J.E.W., Eekelen M.C.J.D. van, Plasmeijer M.J., (1991). "Concurrent Clean", Proceedings of the conference on Parallel Architectures and Languages Europe (PARLE'91). Springer Lecture Notes in Computer Science 505, Vol. II, page 202-219.

....solutions in Section 4, we look in Section 5 how message passing can be added to Concurrent Clean. Section 6 discusses some implementation issues. Section 7 discusses current work on message passing, while Section 8 concludes. 2 Clean and Concurrency 2. 1 Process Annotations Concurrent Clean [NSvEP91] provides a number of process annotations, which are used to create threads in a Clean program. These threads execute concurrently with all other threads: either parallel, on a different processor, or in an interleaved manner on the same processor. There are three kinds of annotations: ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proceedings of Parallel Architectures and Languages Europe, number 506 in LNCS, pages 202--219, Eindhoven, The Netherlands, June 1991. Spinger-Verlag.

....terms of speed and precision is claimed to be a recent implementation by Jensen et al. [JHR94] Their implementation of abstract interpretation using chaotic fixpoint iteration is implemented in C and has not yet been incorporated in any compiler. Another implementation has been given for Clean [NSvP91, PvE93] This implementation is based on abstract reduction [Noc93] It is also written in C. Unfortunately, it is hidden in the Clean compiler and, therefore, comparisons to other implementations are hardly possible. We have developed an adaptation of abstract reduction to Haskell and have ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Ekelen, and M. J. Plasmeijer. Concurrent Clean. In Springer Verlag, editor, Proc of Parallel Architecture and Languages Europe (PARLE'91), number 505 in Lecture Notes in Computer Science, pages 202--219, 1991.

....(developed at Amsterdam University [9] The FAST compiler implements Intermediate, a language that has a syntax similar to Miranda. Intermediate provides more primitive functions than Miranda, but does not support operator overloading and several other features of Miranda. Concurrent Clean [11, 20] is a language primarily intended to be used as target language for a compiler frontend but it has been extended towards a more comprehensive programming language. The implementation is from Nijmegen University. These lazy functional languages have many features in common, the most important being ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In E. H. L. Aarts, J. van Leeuwen, and M. Rem, editors, Parallel architectures and languages Europe (PARLE), LNCS 505/506, pages 202--220, Veldhoven, The Netherlands, Jun 1991. Springer-Verlag.

....the HDGmachine [KLB91] studied the use of independent closures and evaluation transformers in a distributed machine environment. Consequently, very few of these implementations have been been ported to multiple platforms. A notable exception is the Concurrent Clean variant of the Clean language [NSvEP91] a functional language with a strong family resemblance to Haskell. Concurrent Clean extends Clean with a large number of parallel control annotations, which can be used to control parallel computation quite precisely. The language has been implemented on two architectures: a transputer network, ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer, "Concurrent Clean", Proc. PARLE '91 --- Parallel Architectures and Reduction Languages Europe, Springer Verlag LNCS 505/506, 1991, pp. 202--220.

....[11] This system has a two space copying garbage collector. Figure 1 gives an overview of the software that we use for developing functional programs. The Haskell route and the Miranda route should be more integrated than they are at present. It is possible to generate Haskell, Concurrent Clean [13, 19] and LML from advanced Intermediate, so that implementations can be compared using the same benchmark programs [8] The recommended way to use advanced Intermediate is as follows: 1. Develop the program using the Miranda system, freely using the primitives provided by Intermediate (e.g. array ....

E. G. J. M. H. Nocker, J. E. W. Smetsers, M. C. J. D. van Eekelen, and M. J. Plasmeijer. Concurrent Clean. In E. H. L. Aarts, J. van Leeuwen, and M. Rem, editors, Parallel architectures and languages Europe (PARLE), LNCS 505/506, pages 202--220, Veldhoven, The Netherlands, Jun 1991. Springer-Verlag.

....underlying lazy evaluation strategy in order to obtain a more efficient execution [Ben92, Bur87, Bur91, MN92, Myc80, Wad87] The functional language Haskell [HPW92] allows for syntactic annotations on the arguments of constructors of the datatypes. Other lazy functional languages, such as Clean [ENPS92, NSEP92, PE93], allow for more general annotations. The usual way of implementing annotations of this kind can be understood as follows [PE93] A given lazy strategy indicates whether an argument t i of a function call f(t 1 ; t k ) must be evaluated. However, we overcome this rule by evaluating t i ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. Leeuwen, and M. Rem, editors, Proc. of Parallel Architectures and Languages Europe, PARLE'91, LNCS 506:202-219, Springer-Verlag, Berlin, 1991.

....ways exists to implement such a router. This paper presents one based on buffer classes. The router that will be described has been devised for a transputer implementation of Concurrent Clean, an experimental, lazy, higher order parallel functional programming language based on graph rewriting [1,2]. Efficient single processor implementations of this language have been realised at the University of Nijmegen for the Motorola 680x0 processor family and the Sparc [3,4] A prototype implementation for the T800 transputer is being developed, which consists of a transputer code generator and a ....

Nöcker E.G.J.M.H., Smetsers J.E.W., Eekelen M.C.J.D. van, Plasmeijer M.J., (1991). 'Concurrent Clean', Proceedings of the conference on Parallel Architectures and Languages Europe (PARLE'91). Springer Lecture Notes in Computer Science 505, Vol. II, page 202-219.

....the HDGmachine [KLB91] studied the use of independent closures and evaluation transformers in a distributed machine environment. Consequently, very few of these implementations have been been ported to multiple platforms. A notable exception is the Concurrent Clean variant of the Clean language [NSvEP91] a functional language with a strong family resemblance to Haskell. Concurrent Clean extends Clean with a large number of parallel control annotations, which can be used to control parallel computation quite precisely. The language has been implemented on two architectures: a transputer network, ....

E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer, "Concurrent Clean", Proc. PARLE '91 --- Parallel Architectures and Reduction Languages Europe, Springer Verlag LNCS 505/506, 1991, pp. 202--220.

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E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. van Leeuwen, and M. Rem, editors, PARLE '91: Parallel Architectures and Languages Europe, Volume II, volume 506 of Lecture Notes in Computer Science, pages 202--219. Springer, 1991.

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E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. van Leeuwen, and M. Rem, editors, PARLE '91: Parallel Architectures and Languages Europe, Volume II, volume 506 of Lecture Notes in Computer Science, pages 202--219. Springer, 1991.

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E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In PARLE'91 | Parallel Architectures and Languages Europe, LNCS 505, pp. 202-219, Veldhoven, The Netherlands, June 1991. SpringerVerlag. URL: ftp://ftp.cs.kun.nl/pub/CSI/SoftwEng.FunctLang/papers/noce91concurrentclean. ps.gz.

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E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. van Leeuwen, and M. Rem, editors, PARLE '91: Parallel Architectures and Languages Europe, Volume II, volume 506 of Lecture Notes in Computer Science, pages 202--219. Springer, 1991.

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E. G. J. M. H. Nocker, J. E. W. Smetsers, Marko C. J. D. van Eekelen, and Marinus J. Plasmeijer. Concurrent clean. In PARLE (2), pages 202--219, 1991.

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E. G. J. M. H. No cker, J. E. W. Smetsers, M. C. J. D. van Eekelen and M. J. Plasmeijer, `Concurrent Clean', in E. H. L. Aarts, J. van Leeuwen and M. Rem (eds), Proc. Conference on Parallel Architectures and Languages Europe (PARLE '91) Vol. II, Eindhoven, The Netherlands, Springer LNCS 506, June 1991, pp. 202--220.

....that the functional strategy is normalizing for the class of left incompatible term rewriting systems. 1. Introduction An interesting common aspect of the functional languages Miranda 1 (Turner (1985) Haskell (Hudak et al. 1992) Lazy ML (Augustsson (1984) and Clean (Brus et al. 1987) Nocker et al. 1991)) is the similarity between their reduction strategies. The reduction order determined by these strategies can roughly be characterized as topto bottom left to right lazy pattern matching. This reduction order, in the following referred to as the functional strategy, is intuitively easy to ....

Nocker, E.G.J.M.H., J.E.W. Smetsers, M.C.J.D. van Eekelen and M.J. Plasmeijer (1991). Concurrent clean, Proc. of Parallel Architectures and Languages Europe (PARLE'91), Eindhoven, The Netherlands, Springer Verlag, LNCS 505, pp. 202-- 219.

.... rather combinator systems) forms the underlying model for the functional programming language Miranda [Turner 85] term rewriting systems are used in the underlying model for the language OBJ [Futatsugi et al. 85] and graph rewriting systems is the model for the language Clean [Brus et al. 87, Nocker et al. 91] There exists a well understood and well defined notion of type assignment on lambda terms, Supported by the Esprit Basic Research Action 3074 Semagraph . y Partially supported by the Netherlands Organisation for the advancement of pure research (N.W.O. known as the Curry type ....

Nocker E.G.J.M.H., J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In Proceedings of PARLE '91, Parallel Architectures and Languages Europe, Eindhoven, The Netherlands, volume 506-II of Lecture Notes in Computer Science, pages 202--219. Springer-Verlag, 1991.

....the amount of information that is communicated and the moment on which this happens can be important as well. The practical usability and efficiency of the proposed language extensions will be further investigated in the context of the lazy functional graph rewriting language Concurrent Clean (N cker et al. 1991)) ....

Nöcker E.G.J.M.H., J.E.W. Smetsers, M.C.J.D. van Eekelen, M.J. Plasmeijer, Concurrent Clean, in Aarts, E.H.L., J. van Leeuwen, M. Rem (Eds.), Proceedings of the Conference on Parallel Architectures and Languages Europe (PARLE'91) Vol II, Eindhoven, The Netherlands, LNCS 506, pp 202-220, Springer Verlag, June 1991.

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E.G.J.M.H. Nocker, J.E.W. Smetsers, M.C.J.D. van Eekelen, and M.J. Plasmeijer. Concurrent Clean. In E.H.L. Aarts, J. van Leeuwen, and M. Rem, editors, 3rd Parallel architectures and languages Europe (PARLE), volume 505/506 of LNCS, pages 202--220. Springer-- Verlag, 1991.

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Nocker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M., eds., Proceedings of Parallel Architectures and Languages Europe, June, Eindhoven, The Netherlands. LNCS 506, Springer-Verlag, pp. 202-219.

No context found.

Nocker, E.G.J.M.H., Smetsers, J.E.W., Eekelen, M.C.J.D. van, and Plasmeijer, M.J. Concurrent Clean. In Aarts, E.H.L., Leeuwen, J. van, Rem, M., eds., Proceedings of Parallel Architectures and Languages Europe, June, Eindhoven, The Netherlands. LNCS 506, Springer-Verlag, pp. 202-219.

No context found.

E. G. J. M. H. No cker, J. E. W. Smetsers, M. C. J. D. van Eekelen and M. J. Plasmeijer, `Concurrent clean', in E. H. L. Aarts, J. van Leeuwen, and M. Rem (eds), 3rd Parallel Architectures and Languages Europe (PARLE), LNCS 505/506, Veldhoven, The Netherlands, June 1991. Springer-Verlag, pp. 202--220.

No context found.

Nöcker E.G.J.M.H., Smetsers J.E.W., Eekelen M.C.J.D. van, Plasmeijer M.J., (1991). 'Concurrent Clean', Proceedings of the the conference on Parallel Architectures and Languages Europe (PARLE'91). Springer Lecture Notes in Computer Science 505, Vol. II, page 202-219.

No context found.

Nöcker E.G.J.M.H., Smetsers J.E.W., Eekelen M.C.J.D. van, Plasmeijer M.J., (1991). 'Concurrent Clean', Proceedings of the the conference on Parallel Architectures and Languages Europe (PARLE'91). Springer Lecture Notes in Computer Science 505, Vol. II, page 202-219.

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