Hodas, J., & Miller, D. (1990). Representing Objects in a Logic Programming Language with Scoping Constructs. Pages 511-526 of: Warren, D. H., & Szeredi, P. (eds), Proceedins of 7th international conference on logic programming. The MIT Press, Cambridge, MA.  Home/Search   Document Details and Download   Summary   Related Articles   Check

.... is based on the proof as computation metaphor proposed in [4, 3, 38] our connection with models for concurrency is inspired to works in this eld like [11, 13, 27, 37, 38] As an example, in [11] Cervesato shows how to encode Petri Nets in di erent fragments of linear logic like LO, Lolli [24], and Forum [38] exploiting the di erent features of these languages. Algorithmic aspects for veri cation of properties of the resulting linear logic speci cations are not considered in the works mentioned above. The problem of the decidability of provability in fragments of linear logic has ....

Hodas, J., & Miller, D. (1990). Representing Objects in a Logic Programming Language with Scoping Constructs. Pages 511-526 of: Warren, D. H., & Szeredi, P. (eds), Proceedins of 7th international conference on logic programming. The MIT Press, Cambridge, MA.

....within objects, and are consumed right after having been selected for evaluation upon invocation. There are two main contributions over previous work. 1 Firstly, our characterization of object calculi is new, even though it shares ideas with previous presentations of object oriented languages [4, 6, 12, 15] in logic programming. In fact, we depart from the proofs as computations principle of linear logic, distinctive of previous proposals, and rely instead on a standard mechanism of resolution where the result of a computation is a set of answer substitutions binding variables to objects. An ....

J. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In David H. Warren and Peter Szeredi, editors, Proceedings of 7th International Conference on Logic Programming, pages 511-526. The MIT Press, 1990.

....complementary with efforts such as [9, 18, 17, 20] which introduce a more structured notion of logic program, suitable for modular logic programming. It would be particularly interesting to compare our approach with recent developments of this line of research towards objectoriented programming [13]. Finally, we would like to compare it in general with other constructive approaches to logic programming [3, 19] Acknowledgement We are grateful to Alexander Herold, Francois Bry, Andy Dwelly and the ICLP referees for helpful comments on this paper. Thanks are due to Gerard Comyn and Alexander ....

J.S. Hodas and D. Miller. Representing objects in a logic programming language with scoping constructs. In Proc. of the 7th International Conference on Logic Programming, Jerusalem, Israel, 1990.

.... facts, querying facts, and performing hypothetical reasoning ( if I pass CS121 will I graduate ) are easy to model using intuitionistic contexts, updating and retracting facts are not straightforward [3, 9, 19] ffl A notion of state encapsulation can be approximated using intuitionistic logic [15]. An object s state can be represented by assumptions in a context. Updating that state, however, means changing those assumptions. The only change allowed with intuitionistic contexts is that of augmenting the state s representative assumptions. Thus, an object s state becomes progressively more ....

....command to retract a necessary (committed) entry can be executed without any problem (see Figure 8) but it does not have the effect of actually deleting the entry. The kinds of manipulations demonstrated here can be used to correct the notion of state encapsulation and updating that was used in [15]. Our second example of the of course modality is a sim Command: enter(enroll(jane,cs1) Command: check(enroll(jane,X) enroll(jane,cs1) is an entry. Command: upd(enroll(jane,cs1) enroll(jane,cs2) Command: check(enroll(jane,X) enroll(jane,cs2) is an entry. Command: ....

Joshua Hodas and Dale Miller. Representing objects in a logic programming language with scoping constructs. In David D. H. Warren and Peter Szeredi, editors, 1990 International Conference in Logic Programming, pages 511--526. MIT Press, June 1990.

....and intuitionistic assumptions, which would allow very small overhead over classical statically compiled code 13 . The combination of HAGs and linear intuitionistic assumptions is a practical basis for building a semantically clean object oriented extensions on top of Prolog, along the lines of [HM90]. Recently, Bruno Dumant has ported the EDCG package for Life using HAGs. No performance evalution has been performed yet, but the resulting code is much simpler. It would be interesting to port this work to Prolog to be able to fully evaluate and compare translation and HAG based ....

Joshua S. Hodas and Dale Miller. Representing objects in a logic programming language with scoping constructs. In David D. H. Warren and Peter Szeredi, editors, Proceedings of the Seventh International Conference on Logic Programming, pages 511 -- 526. MIT Press, June 1990.

....of formulas since they cannot arbitrarily be duplicated unless they are prefixed by the modality (on the left) and (on the right) and thus each occurrence of the same formula does count in a derivation. 2 According to recent works in the field of Logic Programming [39] and LL Programming [26, 36, 24] it is possible to interpret sequents as descriptions of instant configurations of a computation whose complete behavior is captured by a proof of the sequent itself. Under this perspective the left hand side of a sequent is viewed as a set of program clauses (by choosing only particular classes ....

....uniformity coping with multi conclusion sequents. Forum is a specification language in which it is possible to define the semantics of many aspects of Programming Languages. In fact, among the motivations behind its introduction it is possible to find the need of powerful means to capture updates [26] and concurrency [34] in a purely logical setting. The language is based on a fragment of LL with the following set of connectives: Gammaffi, ....

J. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In D. H. Warren and P. Szeredi, editors, Proceedins of 7th International Conference on Logic Programming, pages 511--526. The MIT Press, Cambridge, MA, 1990.

....the S4 Kripke semantics to the semantics of our language. Furthermore, we investigate the incremental compilation of modules and the so obtained combination of functional and logic programming. By modules certain aspects of object orientation can be captured within a deductive database framework [14]. A major part of our future research will concentrate on this question. Another direction of future research is the declarative formulation of constraints controlling the configuration of modules, which could be based on the notion of a module s signature as proposed e.g. in [22] On the more ....

Hodas J., Miller D.: Representing Objects in a Logic Programming Language with Scoping Constructs. in: Logic Programming, Ed. D. Warren and P. Szeredi, Proc. 7th Intl. Conf. on Log. Progr., MIT Press, 1990, p. 511-526

.... an Object Oriented Logic Programming Language (extended abstract) Giorgio Delzanno, Maurizio Martelli DISI Universit a di Genova, Via Dodecaneso, 35, I 16146 Genova, Italy e mail:fgiorgio,martellig disi.unige.it http: www.disi.unige.it staff giorgio giorgio.html 1 Introduction In [2, 7, 6, 11, 12, 14] higher order intuitionistic and linear logic have been applied in order to define extensions to logic programming languages providing primitives for structuring programs. In particular, higher order linear logic results to be well suited to describe computations based on state transitions as ....

J. S. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In D.H. Warren and P.Szeredi, editors, Proceedings of 7th International Conference on Logic Programming, 511--526. The MIT Press, Cambridge, MA, 1990.

....is enriched by a new condition. It is possible to give alternative formulations of the system, e.g. embedding add into a special version of par. The rule forall requires y not to appear in the lower sequent. This is an important point and it can be exploited to achieve data hiding, as shown in [6, 10]. It is easy to check that each one of the previous rules preserves well formed F O sequents. The most interesting thing of the system is the axiom final. It is introduced to emphasize the idea of proof as computation; this aspect will be discussed in Section 4. Essentially, the form of the final ....

J. S. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In D.H. Warren and P.Szeredi, editors, Proceedins of 7th International Conference on Logic Programming, 511--526. The MIT Press, Cambridge, MA, 1990.

....uniformity coping with multi conclusion sequents. Forum is a specification language in which it is possible to define the semantics of many aspects of Programming Languages. In fact, among the motivations behind its introduction it is possible to find the need of powerful means to capture updates [25] and concurrency [33] in a purely logical setting. The language is based on a fragment of LL with the following set of connectives: Gammaffi, ....

J. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In D. H. Warren and P. Szeredi, editors, Proceedins of 7th International Conference on Logic Programming, pages 511--526. The MIT Press, Cambridge, MA, 1990.

....within complex terms (see [26] and [54] for examples) The second approach, which we consider here, is based on the idea of representing an object as a first order logic theory. This view inspired McCabe s Class Template Language [62] and has been adopted by many other authors in the literature ([35, 34, 40, 66, 48] among others) In his Class Template Language McCabe proposes a logical reconstruction of the OO paradigm where objects are interpreted as sets of axioms defining the objects attributes and methods. The same idea can be exploited to model an OO extension of logic programming using embedded ....

....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 Quantification All of the modular extensions we have considered so far rely on the (stringent) assumption that all the free variables ....

J. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In D.H.D. Warren and P. Szeredi, editors, Proc. 7th Int. Conference on Logic Programming, pages 511--526. The MIT Press, 1990.

....turn. Elements of the list which do not match the pattern are ignored. A filter is a boolean expression; only the bindings which make a filter take the value true are considered. For instance, consider the following list comprehension, y = 3 X ; X A; X 3] if A is [1,2,3,4,5,6] then y is [12,15,18]. List comprehensions are analogous to set comprehensions in mathematics. The above list comprehension is essentially equivalent to the set comprehension: y = 3 X X A and X 3 Furthermore, it can be rewritten as: y = 3 X member(X, A) and greater(X, 3) where member 2 and greater 2 ....

....by integrating the three paradigms with the capability of exploiting multi level parallelism. See Table 2 for a brief summary. Logic Functional ObjectOriented Single level Parallelism Multi level Parallelism LogiC [39] Intermission[19] OOPP[41] CPU[27] DLP[11] OLPSC[15] KSL Logic[17] Orient84 K[18] Vulcan[23] Bridge[21] PROOF[40] FLC[4] CLOS[14] HOPE[9] FUNLOG[34] F [28] LEAF[3] Applog[6] LIFE[2] UNIFORM[20] G[31] L O[26] I Table 2 A summary on the ....

J.S. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In Proceedings of the Seventh International Conference of Logic Programming, MIT Press, 1990, pp. 511-528.

....Id (a (El: S) M) The higher order quantification over a hides all the occurrences of such a constructor in the state and methods formulas. The above break predicate cannot be applied to such objects since constants introduced with pi cannot be binded to free variables outside its scope, see [57, 43]. Private methods. The same idea can be applied in order to define private methods. A method is private in o if it can be invoked only by other methods of o. To accomplish this it is enough to quantify over the names of the private methods. For instance, in the following declaration the method ....

J. Hodas and D. Miller. Representing Objects in a Logic Programming Language with Scoping Constructs. In D. H. Warren and P. Szeredi, editors, Proceedins of 7th International Conference on Logic Programming, pages 511--526. The MIT Press, Cambridge, MA, 1990.

....reasoning about interfaces can be carried out at compile time. In fact, a pre processor could examine required interfaces, determine what methods are applicable for various classes, and add explicit method declarations to those classes. In contrast, various logic programming approaches to objects [2, 13, 16] have focused on using logical inference at the basis of program execution. In contrast, also, Agrawal et al. 1] discuss reasoning about method applicability but do not use the reasoning for deciding applicability. The idea of treating method declarations as assertions can be seen as an ....

Hodas, J. S., and Miller, D. Representing objects in a logic programming language with scoping constructs. In Proceedings of the Seventh International Conference on Logic Programming (1990), D. H. D. Warren and P. Szeredi, Eds., MIT Press, pp. 511--526.

....i.e. modules, can be incrementally compiled. ffl Our approach is extensible towards multi agent systems in a natural way. ffl Optimization techniques of deductive databases carry over unchanged. The representation of objects as logic theories has been proposed by several researchers, e.g. [4, 5, 17, 19, 20, 21]. However, late binding and virtual classes are not addressed. In [8] meta level rules are used to define inheritance and late binding. In [7] 2 a semantics of inheritance and late binding is defined based on composition operators. Both do not deal with virtual classes. 2] define static and ....

J. Hodas and D. Miller. Representing objects in a logic programming language with scoping constructs. In D. Warren and P. Szeredi, editors, Proc. 7th International Conference on Logic Programming, pages 511--526. MIT Press, 1990. 22

....and abstraction facilities. In this paper we propose a way to incorporate modules and data abstraction into a deductive database language, essentially without deviating from pure logic, i.e. the majority of our concepts are supported by the underlying logic language itself. As the results of [11] indicate, it is even possible to represent certain aspects of object orientation within our language. Our basic language is a clausal language with negation as failure as usual in most deductive database systems. As opposed to normal deductive database systems, in our language a subgoal of a rule ....

.... [ fcondition(X) even int(X) g and Bad [ Analyze [ Table [ Count [ f condition(X) odd int(X) g respectively (see also figure 3) While dynamic scoping is suitable for hypothetical reasoning, from a software engineering point of view static scoping should be preferred (see also [14] [11]) Roughly speaking, this can be achieved by applying the following steps 1. Apply standard techniques [23] to compile each program into a separate relationvalued function using the operations of the relational algebra. 13 2. At query compilation time, combine the required operators by ....

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Hodas J. and Miller D.: Representing Objects in a Logic Programming Language with Scoping Constructs, in: Logic Programming, Ed. D. Warren and P. Szeredi, Proc. Seventh Intl. Conf. on Logic Programming, MIT Press, 1990

....in goal formulas provide an important approach to solving certain scoping issues in various applications. See, for example, the notion of gap threading in [PM90] theorem proving using natural deduction proof systems in [FM88] and state encapsulation in object oriented style programming [HM90]. In each of these examples, intuitionistic implications in goals were used and they supplied part of the functionality that was needed. They also illustrated some weakness of intuitionistic logic. In particular, since contexts grow during the search for proofs, it is not possible to have a ....

Joshua Hodas and Dale Miller. Representing objects in a logic programming language with scoping constructs. In David H. D. Warren and Peter Szeredi, editors, 1990 International Conference in Logic Programming, pages 511--526. MIT Press, June 1990.

....higherorder hereditary Harrop formulas while they are not supported by firstorder Horn clauses. Various papers have argued that the scoping and abstraction available in this richer logic can be used to provide for modular programming [Mil89b] abstract data types [Mil89a] and state encapsulation [HM90]. None of these papers, however, have dealt with the problems of programming in the large, that is, the essentially linguistic problems of putting together various different textual sources of code found, say, in different files on a persistent store into one logic program. In this paper, I ....

Joshua Hodas and Dale Miller. Representing objects in a logic programming language with scoping constructs. In David H. D. Warren and Peter Szeredi, editors, 1990 International Conference in Logic Programming, pages 511-- 526. MIT Press, June 1990.

....in goal formulas provide an important approach to solving certain scoping issues in various applications. See, for example, the notion of gap threading in [PM90] theorem proving using natural deduction proof systems in [FM88] and state encapsulation in object oriented style programming [HM90]. In each of these example, intuitionistic implications in goals were used and they supplied part of the functionality that was needed. They also illustrated some weakness of intuitionistic logic. In particular, since contexts grow during the search for proofs, it is not possible to have a formula ....

Joshua Hodas and Dale Miller. Representing objects in a logic programming language with scoping constructs. In David H. D. Warren and Peter Szeredi, editors, 1990 International Conference in Logic Programming, pages 511--526. MIT Press, June 1990.

....me to examine the possibility of designing a logic programming language based on a fragment of Girard s linear logic [2] similar to the hereditary Harrop formula fragment of intuitionistic logic. The first problem involved representing the notion of mutable object state within logic programming [4]. While it is simple to use representative predicates to store the state of an object in the database (or proof context) it is not possible to model the modification of state, since the only change to the database allowed in Prolog is that of stack like augmentation through the use of ....

....problems. Also, in this example, it is assumed that the formula B and the terms t 1 ; t n do not contain occurrences of y 1 ; y m . The implementation of parameterized modules was driven by the need to be able to handle the object oriented programming examples from an earlier paper [4], where they were used to pass initialization information to objects. Nevertheless they have proved useful in a number of instances. For example, the following module defines the shell of a multiset rewriting system, along the lines of the example given in [6, 5] The rewrite rules themselves, ....

Joshua S. Hodas and Dale Miller. Representing objects in a logic programming language with scoping constructs. In David D. H. Warren and Peter Szeredi, editors, 1990 International Conference in Logic Programming, pages 511--526. MIT Press, June 1990.

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