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Interconnection of Object Specifications
 Formal Methods and Object Technology
, 1996
"... ing yet further from reality, we might proscribe the simultaneous effect of two or more methods on an object's state; doing so, we impose a monoid structure on the fixed set of methods proper to an object class. Applying methods one after the other corresponds to multiplication in the monoid, a ..."
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Cited by 8 (2 self)
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ing yet further from reality, we might proscribe the simultaneous effect of two or more methods on an object's state; doing so, we impose a monoid structure on the fixed set of methods proper to an object class. Applying methods one after the other corresponds to multiplication in the monoid, and applying no methods corresponds to the identity of the monoid. A monoid is a set M with an associative binary operation ffl M : M \ThetaM ! M , usually referred to as `multiplication', which has an identity element e M 2 M . If M = (M; ffl M ; e M ) is a monoid, we often write just M for M, and e for e M ; moreover for m;m 0 2 M , we usually write mm 0 instead of m ffl M m 0 . For example, A , the set of lists containing elements of A, together with concatenation ++ : A \ThetaA ! A and the empty list [ ] 2 A , is a monoid. This example is especially important for the material in later sections. A monoid homomorphism is a structure preserving map between the carriers of ...
A Distributed Semantics for FOOPS
, 1995
"... FOOPS is a concurrent objectoriented specification language for which an operational semantics has been provided. This paper gives an equivalent distributed semantics which describes how FOOPS objects cooperate in evaluating a program. The distributed semantics is presented using transition system ..."
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FOOPS is a concurrent objectoriented specification language for which an operational semantics has been provided. This paper gives an equivalent distributed semantics which describes how FOOPS objects cooperate in evaluating a program. The distributed semantics is presented using transition systems. We relate transition systems and sheaves to also give a sheaftheoretic semantics. By implementing the distributed semantics in Eqlog, we obtain a FOOPS simulator. Thus, our distributed semantics is both axiomatic and executable. 1 Introduction This paper gives a distributed operational semantics to FOOPS, a concurrent objectoriented specification language, uses transition systems and sheaf theory in formalising it and proves its equivalence to (a subset of) an already existing operational semantics of FOOPS. FOOPS (Functional and Object Oriented Programming System) combines the functional and objectoriented paradigms in order to offer both a declarative style of design and a notion of...
Distributed Operational Semantics for the Object Paradigm
 Oxford University Computing Laboratory
, 1997
"... this paper we present an approach we call `Distributed Operational Semantics', which models systems of concurrent, interacting objects by diagrams which assign an operational semantics to each object in a system. The behaviour of the whole system is given by a limit construction. In modelling b ..."
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this paper we present an approach we call `Distributed Operational Semantics', which models systems of concurrent, interacting objects by diagrams which assign an operational semantics to each object in a system. The behaviour of the whole system is given by a limit construction. In modelling behaviour by limits we follow earlier work by Goguen on Categorical Systems Theory [4, 5, 6]. This approach pays particular attention to the hierarchical structure of systems, and provides means of constructing systems from component parts in a way that captures both complex objects and parallel composition with synchronisation [16]. The operational semantics of objects can be very general: for example, a semantics for the objectoriented specification language FOOPS has been given by modelling objects as unlabelled transition systems; this semantics is summarised in Section 4.2, and a full account is given in [2]. We shall also present examples of systems that use labelled transition systems. A useful property of the examples we present is that they can be readily translated into specifications in the logic programming language Eqlog [9], which provides both a simulator for the system and a logic for reasoning about systems. Like the sheaf semantics for concurrent objects originating with Goguen [8, 3] and further investigated in [22, 16, 2], our approach is essentially constraint based: interactions between objects constrain their possible behaviours, primarily by synchronising on shared subobjects. Constructing the behaviour of a system by taking its limit corresponds to solving those constraints. It is because of its constraint based nature that the translation into Eqlog is so natural. This paper provides a short introduction to Distributed Operational Semantics; a fuller acco...
Algebraic System Specification and Development: Survey and Annotated Bibliography  Second Edition 
, 1997
"... Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.5.4 Special Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.6 Semantics of Programming Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.1 Semantics of Ada . . . ..."
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Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.5.4 Special Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.6 Semantics of Programming Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.1 Semantics of Ada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.2 Action Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.7 Specification Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.7.1 Early Algebraic Specification Languages . . . . . . . . . . . . . . . . . . . . . . . . 53 4.7.2 Recent Algebraic Specification Languages . . . . . . . . . . . . . . . . . . . . . . . 55 4.7.3 The Common Framework Initiative. . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5 Methodology 57 5.1 Development Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.1.1 Applica...