John S. Conery. Logical Objects. In Proceedings of the Fifth International Conference and Simposium on Logic Programming, August 1988.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... a sequential computation (although the use of lambda terms instead of first order terms, and the fact that clauses may be dynamically loaded in the proof, make things more complex than in the classical case) On the other hand, in a parallel environment, it has been shown in [3, 4, 6] and also in [27, 14, 11], that the formalism of multi headed formulae (e.g. methods here) is better suited, especially for synchronization purposes. Contextual Horn clauses [27] or the logical objects of [14] or Shared Prolog [11] basically correspond to the fragment of LinLog 4 In fact, further refinements would be ....

....classical case) On the other hand, in a parallel environment, it has been shown in [3, 4, 6] and also in [27, 14, 11] that the formalism of multi headed formulae (e.g. methods here) is better suited, especially for synchronization purposes. Contextual Horn clauses [27] or the logical objects of [14], or Shared Prolog [11] basically correspond to the fragment of LinLog 4 In fact, further refinements would be needed to account for the fact that Progression can only be triggered when the context C is flat, and also for the fact that the head of a method may match atoms prefixed with the ....

J.S. Conery. Logical objects. In Proc. of the 5th International Conference on Logic Programming, Seattle, Wa, U.S.A., 1988.

....classical fixed structure inheritance. A more recent solution, known as logic programming with implicit variables [14, 21] is closer to the usual syntax of logic programs but still requires declaring in advance the slots of an object. The use of multiple head clauses has already been proposed in [6, 19]. These systems rely on an extended resolution mechanism, which can be reconstructed in LO using only the connective. Hence, in these systems there is no notion of multiple contexts (corresponding to different objects) as obtained in LO with the connective (duplication rule III) all the ....

J.S. Conery. Logical objects. In Proc. of the 5th International Conference on Logic Programming, Seattle, Wa, U.S.A., 1988. 12

....mentioned [11, 17, 19, 29, 30, 31, 32] efforts which have been focusing on the static aspects (i.e. inheritance) of object oriented programming are described in [2, 9, 12, 16, 21, 33] The framework presented here should provide a theoretical basis for the integration of these two traditions. [10, 28, 8] provide also extensions of Prolog in the direction of object oriented and distributed programming where formulae with multiple heads are allowed; some of the ideas characterizing these approaches are interestingly related to ours, and indeed the systems described therein seem to be logically ....

J.S. Conery. Logical objects. In Proc. of the 5th International Conference on Logic Programming, Seattle, Wa, U.S.A., 1988.

....we have mentioned [6, 12, 14, 22, 23, 24, 25] efforts which have been focusing on the static aspects (i.e. inheritance) of object oriented programming are described in [1, 4, 7, 11, 26] The framework presented here should provide a theoretical basis for the integration of these two traditions. [5] provides also an extension of Prolog in the direction of object oriented programming where clauses with multiple heads are allowed; some of the ideas characterizing this approach are interestingly related to ours, and indeed the system described therein could be logically reconstructed as the ....

J.S. Conery. Logical objects. In Proc. of the 5th International Conference on Logic Programming, Seattle, Wa, U.S.A., 1988.

....has been used and appreciated most widely. Overriding has been a difficult issue to address in logic, as it is related to negation, belief or theory revision, and non monotonic reasoning. Several approaches were appealing in modeling overriding in knowledge representation and in knowledge bases [9, 38, 11, 4, 26, 8, 35, 6, 22, 5, 31, 5, 2, 3, 29, 28, 39, 13, 14, 30, 19]. Most solutions were computationally expensive, or were heavily dependent on the user for capturing the intended semantics i.e, inheritance was almost hand coded into the program. In the latter case, logic did very little in capturing the spirit of overriding and thus, was error prone. ....

J.S. Conery. Logical objects. In R. A. Kowalski and K. A. Bowen, editors, Proc. 5th Int. Conference on Logic Programming, pages 420--434. The MIT Press, 1988.

....by the absence of suitable concurrent goals that would allow synchronization to take place (suspension) In particular, the latter point is tackled by handling suitable hypotheses about the environment of goals. Extended Horn clauses have already been presented in similar forms in [2] 3] [4], 8] 10] 16] 17] and [19] The work reported here differs from them both from the language point of view and from the semantic point of view. From the language point of view, our language differs in three main respects. Firstly, it allows arbitrary sequential and parallel compositions ....

.... We will consider two kinds of messages: reserve(Flight id,Nb seats,Ans) and ask seats(Flight id,Free seats) Their goals are respectively i) to ask for the reservation of Nb seats in the flight Flight id, which yields the answer Ans; 5 This description has actually been inspired by that of [4]. ii) to ask the number of free seats in the flight Flight id. According to the above scheme and using the auxiliary predicates make reservation and free seats, with obvious meanings, the treatment of these messages can be coded as follows. airline syst(DB) Pi reserve(Flight id,Nb ....

J.S. Conery. Logical Objects. In R.A. Kowalski and K.A. Bowen, editors, Proc. 5 th Int. Conf. and Symp. on Logic Programming, pages 420--434, Seattle, USA, 1988. The MIT Press.

....semantics as simple as possible as well as in the main streams of logic programming semantics. However, communicating clauses and synchronized executions raise new problems, for which fresh solutions are proposed. Communicating clauses have already been presented in similar forms in [1] 2] [3], 6] 7] 13] 14] 15] 16] and [20] in the classical logic programming framework. As already said, this paper is a continuation of our previous work [13, 14] In those papers, synchronous communication is expressed in a global and centralized way by extending classical Horn clauses. In ....

....the contextual reduction. 6 The notation is used as syntactic suggar to denote any unit of the program. Hence, the clause is actually a shorthand notation of the set of clauses obtained by replacing by each unit name of the program. 7 This description has actually been inspired by that of [3]. Stacks are identified there by the Id argument of the stack predicate and their state, implemented as a list, moves respectively from S, X S] X S] to [X S] S, X S] according as a push, pop or top message is received. The classical airline reservation system provides another ....

J.S. Conery. Logical Objects. In R.A. Kowalski and K.A. Bowen, editors, Proc. 5 th Int. Conf. and Symp. on Logic Programming, pages 420--434, Seattle, USA, 1988. The MIT Press.

....This is in contrast with our approach where the definition of rebinding is completely clear as to what the mapping is at each point. Several approaches deal with updates by using clauses with multiple heads and passing state in arguments to goals. An early paper following this style is Conery s [12]. Two types of literals are used: object literals (representing objects) and procedure literals (representing methods) An object clause has one of each type of literal in its head and represents a method call on a particular type of object, the object in the head being consumed in the reduction ....

John S. Conery. Logical objects. In Robert A. Kowalski and Kenneth A. Bowen, editors, Proceedings of the Fifth International Conference and Symposium on Logic Programming, pages 420--434. MIT Press, 1988.

....definitions, supporting a programming methodology typical of languages like Object Calculi [1] Thus, it embeds some aspects typical of both functional and imperative OO languages. In the LP context , some of the above mentioned aspects of OO programming have been studied in other approaches [3, 8, 9, 10, 15]; 2] is the approach which is closest to YahOO and the main differences are discussed in [4] 2 Designing YahOO The following presentation of the OO programming aspects of F O resulted from the attempt of maintaining a logic programming flavor while adopting a standard syntax for class and ....

J. S. Conery. Logical Objects. In R.A. Kowalski and K.A. Bowen, editors, Proceedings of 5th International Conference on Logic Programming, 420--434. The MIT Press, Cambridge, MA, 1988.

....as completely concurrent activities. According to Peter Wegner s classification of OO languages [14] classbased languages enjoy such set of features. In many logic models of OO features, methods are represented by logic clauses and used to rewrite the state of an object into a new one, see [2, 4, 9]. From this perspective, in order to model encapsulation it is necessary to resort to a higher order logic, where clauses can be handled at the object level. At the same time, standard logic approaches to the problem of state modifications seem unsuitable here, while Linear Logic (LL) 5] ....

....between F O and Forum, hence full LL. Section 5, the main part of the paper, contains the description of the above mentioned OO features in F O. The main idea is to represent objects as particular atoms that can be handled by methods using an approach similar to the one shown by Conery in [4] and re considered by Andreoli and Pareschi in [2] inside the LL setting. However, there are many differences between the latter and the work presented in this paper. Andreoli and Pareschi considered objects as collections of slots spread in the right hand side of a sequent, i.e. in parallel. ....

J. S. Conery. Logical Objects. In R.A. Kowalski and K.A. Bowen, editors, Proceedins of 5th International Conference on Logic Programming, 420--434. The MIT Press, Cambridge, MA, 1988.

....with respect to the entailment relation of the corresponding modal framework. The proposed semantics represents to our knowledge the first attempt to capture a truly logical semantics of encapsulation in deductive object oriented languages. 1 Introduction There have been several attempts [9, 10, 1, 5, 11, 2, 16] at combining logic programming with object oriented concepts like object identity, complex objects, methods, encapsulation, signatures, inheritance, etc. in a clean mathematical framework. Most of the approaches either fall short of capturing the essential set of properties of object orientation ....

J.S. Conery. Logical objects. In R. A. Kowalski and K. A. Bowen, editors, Proc. 5th Int. Conference on Logic Programming, pages 420--434. The MIT Press, 1988.

....to attributes. Objects, therefore, are literals, with arguments instantiated with concrete attribute values. In Mandala [FTK. 84] objects are predicates, with one argument meant for indicating the revision (in the form of a stream) and others for attribute values. In Conery s merger [Con88], where predicate interpretation changes during the program execution, classes are predicates, with one argument meant for an atomic object name, and others corresponding to attributes. In Objects as Intensions [CW88] an object is an individual variable, standing for the infinite list of its ....

J. S. Conery. Logical objects. In Logical Programming: Proc. 5th Int'l Conf. and Symp., Seattle, Aug 1988, pp 420-34. Cambridge, MA: The MIT Press, 1988.

....reasoning. Another promising approach to state representation is Meseguer and Mart i Oliet s Rewriting Logic [Mes92, MOM93] Linear Objects (LO) of Andreoli and Pareschi is the first proposal for integration of OOP and LP based on LL. Technically LL bears similarity to an earlier proposal [Con88] in that both approaches allow multiple atoms in the head of the clauses. The novelty of LL is its firm foundation in LL, which provides both a standard model theoretic semantics based on phase spaces [AP91a, Section 2.4] see also [CC94] and proof theoretical insights for the design of the ....

John S. Conery. Logical objects. In Robert A. Kowalski and Kenneth A. Bowen, editors, Intl. Conf. and Symp. on Logic Programming (ICLP'88), pages 420--434, 1988.

....has been proposed by Chen and Warren in [27] where intensional variables are introduced to keep track of state changes without side effects. In other proposals [35, 66] state change is simulated by means of unification and recursion within a concurrent logic programming framework. In [3] and [28], multi headed clauses are used for similar purposes whereas a (goal) continuation passing style of programming is used in [48, 49, 47] The interested reader should refer to these references for a fuller description of these issues and of the different proposals. 3.7. Lexical Scoping as Universal ....

J.S. Conery. Logical objects. In R. A. Kowalski and K. A. Bowen, editors, Proc. 5th Int. Conference on Logic Programming, pages 420--434. The MIT Press, 1988.

....be considered as a primitive notion of objects with state, and the assignment construct as a special method. This idea has been reconsidered in other approaches, as we will discuss in the sequel of this Section. Objects as atomic goals. Another approach to model state updates has been shown in [19]. In this approach, close to the concurrent interpretation of Prolog as we will describe later, objects are denoted by particular atomic goals. In order to define methods for this representation of objects, Horn Clauses have been extended by considering heads with multiple heads, as in the stack ....

J.S. Conery. Logical objects. In R.A. Kowalski and K.A. Bowen, editors, Proceedins of 5th International Conference on Logic Programming, pages 420--434. The MIT Press, Cambridge, MA, 1988.

.... A famous work on Object Oriented Logic Programming is the language Linear Objects (LO) developed by Andreoli and Pareschi at ECRC, Germany [13, 15] They have written many papers on LO, their focus shifting initially from state representation (similar to an earlier proposal of John Conery [47]) later to concurrency issues (described in Section 4) In their approach, an object is a multiplicative disjunction of attribute literals, which as a whole is a free floating additive conjunct in the solution containing all objects. I will describe here only one feature of their model, builtin ....

J. S. Conery. Logical objects. In R. A. Kowalski and K. A. Bowen, editors, Fifth International Conference and Symposium on Logic Programming, pages 420--434, 1988.

....and non deterministic, and it is possible not only to search for objects with certain properties but also to do hypothetical reasoning with them. 1 Introduction Many attempts have been made in recent years to extend logic programming with features found in object oriented programming languages [2,3,5,6,12,9]. Much of this work has used Prolog and Horn clause as a foundation. In this paper, we start with an enrichment of Horn clause logic that contains a natural scoping mechanism and then show how aspects of object oriented programming can be represented. Our account of state and state updates is the ....

John S. Conery. Logical objects. In R. Kowalski and K. Bowen, editors, Logic Programming: Proceedings of the 5th International Conference and Symposium, pages 420--434. MIT Press, 1988.

....Variables in the label are universally quantified over the whole theory. Special rules, called class rules, are used to inherit from other objects. McCabe s book [22] gives many examples of L O programs. There are many other approaches to object oriented logic programming. See for example [23, 1, 2, 11, 26, 4, 10] and the survey by Davison [12] The approach we take differs from McCabe s in several key points. The notion of object is superficially the same in both approaches but the relationship to classes is different. In L O objects are instantiations of a parametrised theory (classes are not explicitly ....

John S. Conery. Logical objects. In Robert A. Kowalski and Kenneth A. Bowen, editors, Proceedings of the Fifth International Conference and Symposium on Logic Programming, pages 420--434. MIT Press, 1988.

....space, restrictions should be imposed on the way these additional heads are pursued. This section describes two proposals which, although stemming from different grounds and having different formal justifications, nevertheless end up in a quite similar form. Logical Objects was proposed by Conery [18, 17, 19] in 1987. It introduces a new kind of literals object literals whose arguments carry the object state (similarly to Section 5) However the thread of control is not programmed as a message stream held by the object, but more in the spirit of conventional Prolog using normal literals (Conery ....

....these goals are consumed and the clause is executed. object(ID,State) mesg : change(State,NewState) object(ID,NewState) contrast this with the example in Section 5) The merit of this approach is that is does not depend on a Concurrent Prolog implementation: the language Hoops described in [19] is normal backtracking Prolog. Object state in the Concurrent Prolog approach is held in a suspended (waiting for a message) process, while in this approach the object literals in the goal are suspended ( pushed back in the set of goals) until a suitable procedure literal is available. ....

J. S. Conery. Logical objects. In R. A. Kowalski and K. A. Bowen, editors, Fifth International Conference and Symposium on Logic Programming, pages 420--434, 1988.

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John S. Conery. Logical Objects. In Proceedings of the Fifth International Conference and Simposium on Logic Programming, August 1988.

No context found.

John S. Conery. Logical objects. In Proceedings of the Fifth International Conference and Simposium on Logic Programming, August 1988.

No context found.

J.S. Conery. Logical objects. In R.A. Kowalski and K.A. Bowen, editors, Proceedins of 5th International Conference on Logic Programming, pages 420--434. The MIT Press, Cambridge, MA, 1988.

No context found.

John S. Conery (1988) Logical objects, proc. 5th Int. Conf. on Logic Programming, pages 420--434.

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