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Papers available in this directory in .ps.gz format:
FST-TCS90
---------
R. Breu and E. Zucca
An Algebraic Compositional Semantics of an Object Oriented Notation with Concurrency.
In C.E. Veni Madhavan, editor,
Foundations of Software Technology and Theoretical Computer Science,
number 405 in Lecture Notes in Computer Science, pages 131-142.
Springer Verlag, Berlin, 1990.
Abstract:
This paper presents an algebraic compositional semantics for a schema of an
object-oriented syntax which models many existing features as class hierarchies,
polymorphism and concurrency, using a pattern which could be applied to different
concrete languages. The semantics is defined in a classical denotational style, i.e.
giving an abstract syntax, the semantic domains and the interpretation of the syntactic
operators.
The given semantics is algebraic in the sense that the value denoted by a class is a
class of algebras described by an algebraic specification. A class combinator (e.g.
inheritance) is semantically interpreted in this framework as a function which handles
classes of algebras or, in an equivalent way, as a specification combinator. Moreover,
our schema of semantic definition allows to model also concurrent features if any, by
underlying an approach to concurrency based on algebraic transition systems.
MFCS93
------
E. Astesiano, G. Reggio, and E. Zucca.
Stores as Homomorphisms and Their Transformations.
In A. M. Borzyszkowsky and S. Sokolowsky, editors,
Mathematical Foundations of Computer Science 1993,
number 711 in Lecture Notes in Computer Science, pages 242-251.
Springer Verlag, Berlin, 1993.
Abstract:
In the classical denotational model of imperative languages handling structured types,
like arrays, requires an ad-hoc treatment for each data type, including e.g. an ad-hoc
allocation and deallocation mechanism. Our aim is to give a homogeneous approach that
can be followed whichever is the data structure of the language.
We start from the traditional model for Pascal-like languages, which uses a notion of
store as a mapping from left values (containers for values, usually called locations),
into right values; we combine this idea with the well-known algebraic approach for
modelling data types. More precisely, we consider an algebraic structure both for the
right and the left values; consequently, the store becomes a homomorphic mapping of
the left into the right structure.
Seeing a store as a homomorphism has a number of interesting consequences. First
of all, the transformations over a store can be uniformly and rigorously
defined on the basis of the principle that they are minimal variations
compatible with some basic intended effect (e.g., some elementary substitution).
Thus semantic clauses too, which rely on these transformations as auxiliary
functions, can be given uniformly; for example, we can give a unique clause for
assignment for any data type in Pascal and Ada-like languages.
Volkse
------
E. Astesiano and E. Zucca.
A Semantic Model for Dynamic Systems.
In U.W. Lipeck and B. Thalheim, editors,
Modelling Database Dynamics, Volkse 1992, Workshops in Computing, pages 63-83.
Springer Verlag, Berlin, 1993.
Abstract:
We present a new formal structure, called d-oid, for modelling systems of evolving
objects. In our view, d-oids are the dynamic counterpart of many-sorted algebras, in
the sense that they can model dynamic structures as much as algebras can model
static data types. D-oids are a basis for giving syntax and semantics for kernel
languages for defining methods; these languages are built over what we call method
expressions, like applicative kernel languages are built over terms. Moreover some
hints are given towards modelling classes and inheritance.
MSCS
----
E. Astesiano and E. Zucca.
D-oids: a Model for Dynamic Data-Types.
Mathematical Structures in Computer Science.
Vol. 5, number 2, pp. 257-282.
June 1995.
(DISI-TR-94-16)
Abstract:
We propose a semantic framework for dynamic systems which, in a sense,
extends the well-known algebraic approach for modeling
static data structures to the dynamic case.
The framework is based on a new mathematical structure, called d-oid, consisting of
a set of instant structures and a set of dynamic operations. An instant structure
is a static structure, e.g. an algebra; a dynamic operation is a transformation of
instant structures with an associated point to point map, which allows to keep track
of the transformations of single objects and thus is called tracking map. By an
appropriate notion of morphism the d-oids over a dynamic signature constitute a
category.
It is shown that d-oids can model object systems and support an abstract notion of
possibly unique object identity; moreover, for a d-oid satisfying an identity
preserving condition, there exist an essentially equivalent d-oid where the elements
of instant structures are just names.
JCSS
----
E. Astesiano and E. Zucca.
A Free Construction of Dynamic Terms.
Journal of Computer and System Sciences.
Vol. 52, number 1, pp. 143-156.
February 1996.
(DISI-TR-94-25)
Abstract:
In this paper we show that it is possible to extend in a natural way to the dynamic
case some basic results of the classical approach to (static) data types. Within an
appropriate framework of dynamic structures (called d-oids), which play the same role
of algebras in the static case, we define a language
of dynamic terms, also enjoying the property of unique canonical representation;
moreover dynamic terms constitute a free structure whenever the static terms in the
underlying static framework are so. As a main application of the above construction,
we get a rather elegant kernel language for recursive definitions of dynamic derived
operations, which parallels the well-known McCarthy's schema for a kernel applicative
language. This kernel language can be seen also as a metalanguage for expressing the
semantics of concrete (e.g. imperative or object based) languages.
WADT95
------
E. Zucca.
Implementation of Data Structures in an Imperative Framework.
In Recent Trends in Data Type Specification '94
(10th Workshop on Specification of Abstract Data Types joint with the 5th COMPASS Workshop
- Selected Papers),
number 906 in Lecture Notes in Computer Science, pages 483-498,
Berlin, 1995. Springer Verlag.
(DISI-TR-94-28)
Abstract:
We present a formal definition of implementation between concrete structures within
the framework of dynamic data-types. The main outcome is an adequate and uniform
semantic model for stating when a software module in an imperative or object
based language is a correct implementation of a data structure. Moreover, the
definition is obtained extending in a natural way the notion used in the static case,
showing that our dynamic frameworks are a ``sound'' generalization
of static frameworks.
MFCS96
------
E. Zucca.
From Static to Dynamic Abstract Data-Types.
In W. Penczek and A. Szalas, editors,
Mathematical Foundations of Computer Science 1996,
number 1113 in Lecture Notes in Computer Science, pages 579-590.
Springer Verlag, Berlin, 1996.
Abstract:
We show how to extend in a canonical way a given formalism for specifying
(static) data types (like usual algebraic specification frameworks) with dynamic features.
What we obtain in this way is a
corresponding formalism for specifying dynamic data-types based on the
"state-as-algebra" approach: a dynamic data-type models a
dynamically evolving system in which any state can be viewed as
a static data type in the underlying formalism, and the dynamic evolution is given
by operations handling states. Formally, our construction is a transformation
of (pre)institutions.
FAC96Short
----------
R. Breu and E. Zucca
An Algebraic Semantic Framework for Object Oriented Languages with Concurrency
(Extended Abstract, 10 pages).
Formal Aspects of Computing, Vol.8, number 6, pages 706-715, 1996.
Abstract: This paper presents an algebraic semantics for a schema of
object oriented languages including concurrent features. A class, the basic
syntactic unit of object oriented languages, denotes a set of algebras determined
by an algebraic specification. This specification describes a system of (possibly
active) objects interacting via method calls. Extending other approaches,
structured classes are modelled in a fully compositional way. This means that the
semantic counterpart of class combinators like inheritance and clientship are
specification combinators. A model of records with sharing allows us to describe
typical object oriented features like object sharing, inheritance polymorphism and
dynamic binding. For modelling how objects evolve in a concurrent environment, we
rely on an algebraic description of labelled transition systems.
FAC96Full
---------
R. Breu and E. Zucca
An Algebraic Semantic Framework for Object Oriented Languages with Concurrency.
(Full Version, 45 pages).
Formal Aspects of Computing (electronic supplement), Vol.8E, number 6, 1996.
(DISI-TR-95-02, 1994)
TCS98
-----
E. Zucca.
From Static to Dynamic Abstract Data-Types: an Institution Transformation.
Theoretical Computer Science, Vol 216, Issue 1/2, March 1999.
(DISI-TR-96-1, 1996)
Abstract:
We show how to extend in a canonical way a given formalism for specifying
(static) data types (like usual algebraic specification frameworks) with dynamic
features.
What we obtain in this way is a corresponding formalism for specifying
dynamic data-types based on the "state-as-algebra" approach: a dynamic data-type
models a dynamically evolving system in which any state can be viewed as
a static data type in the underlying formalism, and the dynamic evolution is given
by operations handling configurations. Formally, our construction is a functor between
two appropriate categories of (specialized) institutions.
SCP98
-----
E. Astesiano, G. Reggio and E. Zucca
Stores as Homomorphisms and Their Transformations - A Uniform Approach to
Structured Types in Imperative Languages
Science of Computer Programming, Vol. 34 Issue 3, pag.163-190, June 1999.
(DISI-TR-94-14, 1994)
Extended version of MFCS93 (Stores as Homomorphisms and Their
Transformations)
Abstract: We address the problem of giving a clean and uniform mathematical
model for handling user defined data types in imperative languages, contrary to
the ad-hoc treatment usual in classical denotational semantics.
The problem is solved by defining the store as a homomorphic mapping of an
algebraic structure of left values modelling containers into another one of
right values modelling contents. Consequently store transformations can be
defined uniformly on the principle that they are minimal variations of the
store embedding some basic intended effects and compatible with the
homomorphic structure of the store.
FAC99
----------------
P. Audebaud and E. Zucca
Deriving Proof Rules From Continuation Semantics
Formal Aspects of Computing, 11(4), 1999.
(RR 97-19, LIP-ENS Lyon, 1997)
Abstract: We claim that the continuation style semantics of a programming language
can provide a starting point for constructing a proof system for that language. The
basic idea is to see weakest precondition as a particular instance of continuation
style semantics, hence to interpret correctness assertions (e.g. Hoare triples)
as inequalities over continuations. This approach also shows a
correspondence between labels in a program and annotations.
Last update 18 August 1999