Goguen, J. A. / Wolfram, D. "On Types and FOOPS" Proceedings of the IFIP 1990 Conference on OODB (Windermere, U.K.); Elsevier Science Publishers  Home/Search   Document Not in Database   Summary   Related Articles   Check

....the specification of reactive systems, conceptual modeling and knowledge representation. Approaches to logic and algebraic foundations of object orientation and concurrency have given essential input to the work reported here. The results in [FM91, FM92, SSC92] have been influential. FOOPS [GW90] has provided insights in the algebraic nature of objects. Algebraic approaches to concurrency are given in [AR92, MM93] DTL is influenced by the n agent logic in [LMRT91, Th94] but we deviate from that logic in essential respects: we have more elementary temporal operators, and our ....

J. A. Goguen and D. Wolfram. On Types and FOOPS. In: R. Meersman, W. Kent, and S. Khosla (eds.). Object-Oriented Databases: Analysis, Design and Construction (Proc. 4th IFIP WG 2.6 Working Conference DS-4, Windermere (UK)), Amsterdam, 1991. North-Holland

....be structured in terms of smaller theories, and why this structuring is important for defining views and for the subsequent reification phases. On the other hand, we show how a straightforward notion of subclass may be defined through subsorting and interpretations between theories (what in FOOPS [33] corresponds to sub modules) We show how interconnections between objects can be established, namely by specifying which actions they share, following the general categorial principle established in [30] and which suggests that a complex system is explained in terms of a diagram that depicts its ....

....12 J.FIADEIRO, C.SERNADAS, T.MAIBAUM AND A.SERNADAS This subtype relation leads us half way to the notion of subclass. The other half is related to the identification of the instances of the subclass. The relationship between the two identification sorts is easily formalised as in FOOPS [33] (leading to what in FOOPS corresponds to sub modules rather than sub classes) by using the sort inheritance mechanism available in order sorted algebra [32] That is, we assume that we have sorts ordered in a semi lattice so that a sort may be declared as being a subsort of another sort, meaning ....

J.Goguen and D.Wolfram, "On Types and FOOPS", in [45]

....are required. This is more stringent than Proposition 5.1 states from the type safety point of view it is sufficient to require that the type of the substituted object is a refinement of the constrained type. However, this in general leads to the problem of unintended substitutability [10, 7], e.g. substituting a Person object by a Wine object because they just happen to have the same functional specification consisting of Name and Age attributes. Our view is that the user should indicate the desire for substitutability explicitly by relating the types accordingly in the subtype ....

J. A. Goguen and D. Wolfram. On types and FOOPS. In Proc. IFIP TC-2 Conf. on Object-Oriented Databases, Windermere, UK, Jun 90.

....of objects) are grouped into (visible) sorts, whereas objects themselves are grouped into so called hidden sorts. Hidden sorts are defined as sets of algebrae, which are nothing less than semantic counterparts of theories or modules. A thorough justification of this approach can be found in [GW91]. 3 Principles and Terminology The principles of OO have two aspects, facilitating and restrictive. An OO language must possess constructs for working with objects (modularity) There must be constructs for expressing explicit calls to objects (e.g. message passing) but certain calls may be ....

J. A. Goguen and D. Wolfram. On types and FOOPS. In R. Meersman et al., eds., Object Oriented Databases: Analysis, Design and Construction, pp 122. Amsterdam: North-Holland, 1991.

....Development Organization) y Supported in part by Defense Advanced Research Projects Agency and Rome Laboratory under Contract F30602 92 C 0140. for example work by Maier on O logic [26] work by Kifer and Lausen on F logic [23] work by Goguen, Meseguer and Wolfram on the FOOPS language [17, 21], work by Beeri and Milo on algebraic foundations [8, 9, 10] and work by Abiteboul on method schemas [4, 3] see [23, 9] for additional references in this whole area) However, it seems fair to say that no agreement has yet been reached on the matter of foundations, and that many problems remain ....

....for class inheritance, and to provide module inheritance mechanisms to do the job of code modification. This distinction between the level of classes (more generally sorts) and the level of modules was already clearly made in the FOOPS language (besides the original paper [17] see also [21] for a very good discussion of inheritance issues and of the class module distinction in the context of FOOPS) and indeed goes back to the distinction between sorts and modules in OBJ [20] In MaudeLog, code in modules can be modified or adapted for new purposes by means of a variety of module ....

J. Goguen and D. Wolfram. On types and FOOPS. In Proc. IFIP Working Group 2.6 Working Conference on Database Semantics: Object-Oriented Databases: Analysis, Design and Construction, 1990.

....community is changed by event occurrences. Finally, in Sect. 5 we compare TROLL light with TROLL and semantic data models, and conclude with some remarks concerning future investigations. 2 Data Level Today, the differences between data and objects are well known and widely accepted [Bee90, GW91, SE91] For example, the instance 5 of data sort int is a universally known abstraction. In contrast, an instance of object sort employee is an application specific abstraction. For the number 5 there exists a common natural representation by a printable value, while an employee can only find an ....

J.A. Goguen and D. Wolfram. On Types and FOOPS. In Meersman et al.

....updated its intended meaning is destroyed. This misuse can be prevented by declaring that empty is private to STACK OF NAT (and indeed rest would need to be private too, so that empty could not be accessed indirectly either) The details of this facility are still under consideration, though; see [32] for some general discussion about it. Finally, note that because of the default value conventions new.Stack( creates an empty stack (as determined by is empty) Warning: Default values are not computed for attributes of entry time objects. 3.3.3 Metaclasses Sometimes there is a need to define ....

J. Goguen and D. Wolfram. On Types and FOOPS. In R. Meersman, W. Kent, and S. Khosla, editors, Proceedings of the IFIP TC2 Working Conference on Database Semantics: ObjectOriented Databases: Analysis, Design and Construction, Windemere, United Kingdom, July 1990.

....multiple substitutability. Multiple substitutability is a necessary means to solve modeling problems arizing if one wants to 1 This is independent of the subtype relationship used. For instance applying a subtype relationship based on structural or name equivalence (see [2] and [7] resp. and [4] for a comparison) does not make any difference for the problems studied here. Both exhibit the same problems. ffl look at the whole object as a part, or ffl look at a part of an object as a (or the) whole object. We discuss each of these areas separately. It is often convenient to ....

J. A. Goguen and D. Wolfram. On types and FOOPS. In Proc. IFIP TC-2 Conf. on Object-Oriented Databases, Windermere, UK, Jun 90.

....[Ch76, Bo85, EGH 92, SF91, SJH93] and knowledge representation [ST89, MB89] Approaches to logic and algebraic foundations of object orientation and concurrency have given essential input to the work reported here. The results in [FSMS91, FM91, FM92, SSC92] have been influential. FOOPS [GM87, GW90] has provided insights in the algebraic nature of objects. Algebraic approaches to concurrency are given in [AR92, MM93, Br93] The local specification logic and interpretation structures put forward in this paper are influenced by the n agent logic in [LMRT91] but we deviate from that logic in ....

J. A. Goguen and D. Wolfram. On Types and FOOPS. In: R. Meersman, W. Kent, and S. Khosla (eds.). Object-Oriented Databases: Analysis, Design and Construction (Proc. 4th IFIP WG 2.6 Working Conference DS-4, Windermere (UK)), Amsterdam, 1991. North-Holland

....that theoretical foundations for object oriented concepts and constructions do not have found so wide attention yet. Matters are changing slowly: there are formal approaches to object oriented programming language semantics [CP89] database concepts [Be91, GKS91] and specification languages [GW90]. Besides this, also language and system independent discussions of fundamental object oriented issues are evolving [Cu91, HC89, LP90] In the IS CORE working group, we have been working in the latter direction. Recent contributions to semantic fundamentals are [ESS90, ES90, EGS91, CS91, ....

Goguen, J.; Wolfram, D.: On Types and FOOPS. Proc. IFIP 2.6 Working Conference DS-4, Meersman, R.; Kent, W. (eds.), North--Holland, Amsterdam 1991

....that theoretical foundations for object oriented concepts and constructions do not have found so wide attention yet. Matters are changing slowly: there are formal approaches to object oriented programming language semantics [CP89] database concepts [Be91, GKS91] and specification languages [GW90] Besides this, also language and system independent discussions of fundamental object oriented issues are evolving [Cu91, HC89, LP90] In the IS CORE working group, the first and third authors have been cooperating in the latter direction. Recent contributions to semantic fundamentals are ....

....specialization aggregation big to small single abstraction interfacing big to small multiple generalization synchronization For each of these cases, we also have the encapsulated variant where the epimorphisms are retractions. 3 Object Oriented Specification Approaches 3. 1 FOOPS FOOPS [GM87, GW90] Functional Object Oriented Programming System) is an object oriented programming system with a declarative functional style. It is designed to preserve the essence of both functional and object oriented programming: functional programming provides abstract data types for object attribute ....

Goguen,J.;Wolfram,D.: On Types and FOOPS. Proc. IFIP 2.6 Working Conference DS-4, Meersman,R.;Kent,W. (eds.), North--Holland, Amsterdam 1991

....hidden, and vice versa. 3.2 Inheritance and Modularity There are many opinions about what inheritance is or should be. We believe that much confusion has resulted from not distinguishing carefully between subclasses and imported modules, or more fundamentally, between classes and modules (see [26] for a more detailed discussion of this) We believe that each of these is needed, and that they are di erent. Similarly, there are many di erent notions of encapsulation, which can also become confused by failure to distinguish between modules and classes. In our opinion, the fundamental notion ....

....by failure to distinguish between modules and classes. In our opinion, the fundamental notion of inheritance is at the module level rather than at the class level. Also, we believe that modules should support the declaration of more than one class (examples showing the need for this are given in [26]) The basic intuition about modules is that they should support the reuse or replacement of code [31] This requires that the properties of an imported module should be preserved by its importing module: we want old classes to behave the same way in their new context as they did in their ....

Joseph Goguen and David Wolfram. On types and FOOPS. In Robert Meersman, William Kent, and Samit Khosla, editors, Object Oriented Databases: Analysis, Design and Construction, pages 1-22. North Holland, 1991.

....USA. SRI International, Menlo Park CA 94025, USA. Japan Advanced Institute of Science and Technology, 1 1 Asahidai, Tatsunokuchi, Ishakawa, Japan. Universit e de Paris Sud, 91405 Orsay, France. OBJ3 has been used for building FOOPS, an object oriented specification and programming system [74, 87], the Eqlog system [71, 72, 25] for equational logic (or relational) programming, OOZE [3] an object oriented specification language influenced by Z [142] the 2OBJ metalogical framework theorem prover [81] and TOOR [130] a system for tracing requirements. OBJ has been used for many ....

....University [143] UMIST OBJ has been made available as a proprietary software product from Gerrard Software, under the name ObjEx. OBJ has been extended in many directions, including logic (or relational) programming (the Eqlog system [71, 72, 25] object oriented programming (the FOOPS system [74, 87]) object oriented specification (OOZE [3] requirements tracing (TOOR [130] higher order functional programming [97, 110] and LOTOS style specification for communication protocols [127, 128] Recent developments within the OBJ community include CafeOBJ, Maude, and CASL. CafeOBJ [26, 27] is ....

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Joseph Goguen and David Wolfram. On types and FOOPS. In Robert Meersman, William Kent, and Samit Khosla, editors, Object Oriented Databases: Analysis, Design and Construction, pages 1--22. North Holland, 1991.

....example, a method which has the identifier of a non existent object as an actual parameter and which is strict in that parameter should evaluate to . We distinguish between objects and data: objects are mutable and can contain data, but data are fixed and are not objects and do not contain them [17]. Objects can send messages to each other. Each message contains an address which is the identifier of its intended recipient, and an object can only receive a message which contains its own identifier as its address. Each message also contains a procedure call or method expression which is ....

....algebraic geometry, differential equations, and category theory. The formulation of sheaf semantics we use is based on that by Goguen [10] It is has been used to give a sheaf theoretic semantics of concurrency in the combined functional and object oriented programming language called FOOPS [9, 17]. 4 Sheaves, Diagrams, and Behaviour The following definitions are sufficiently general for our discussion of sheaf models of concurrency. Definition 4.1 A sheaf is a contravariant functor O : T op Set such that all of the following conditions hold: ffl T is a base category whose set of ....

J.A. Goguen and D.A. Wolfram, Types and FOOPS, Proceedings of the IFIP Working Group 2.6 Working Conference on Database Semantics: Object Oriented Databases: Analysis, Design & Construction, International Federation for Information Processing, North-Holland, Amsterdam, 1991, 1--22.

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Goguen, J. A. / Wolfram, D. "On Types and FOOPS" Proceedings of the IFIP 1990 Conference on OODB (Windermere, U.K.); Elsevier Science Publishers

No context found.

J. Goguen and D. Wolfram. On types and FOOPS. In Proceedings IFIP TC-2 Working Conference on Database Semantics, 1990.

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J. A. Goguen and D. Wolfram. On types and FOOPS. In Proc. IFIP TC-2 Conf. on Object-Oriented Databases, Windermere, UK, Jun 90.

No context found.

J. Goguen and D. Wolfram. On types and foops. In R. Meersman, W. Kent, and S. Khosla, editors, Object Oriented Databases: Analysis, Design and Construction, pages 1--22. North Holland, 1991.

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