scholarly journals Virtual Classes - a powerful mechanism in object-oriented programming

1989 ◽  
Vol 18 (283) ◽  
Author(s):  
Ole Lehrmann Madsen ◽  
Birger Møller-Pedersen
Keyword(s):  
Object Oriented ◽  
Object Oriented Programming ◽  
Powerful Technique ◽  
General Properties ◽  
Key Concepts ◽  
Virtual Class ◽  
Virtual Classes ◽  
Powerful Mechanism ◽  
Object Oriented Languages ◽  
Typed Languages

The notations of class, subclass and virtual procedure are fairly well understood and recognized as some of the key concepts in object-oriented programming. The possibility of modifying a virtual procedure in a subclass is a powerful technique for specializing the general properties of the superclass.<p>In most object-oriented languages, the attributes of an object may be references to objects and (virtual) procedures. In Simula and BETA it is also possible to have class attributes. The power of class attributes has not yet been widely recognized. In BETA a class may also have <em>virtual class attributes</em>. This makes it possible to defer part of the specification of a class attribute to a subclass. In this sense virtual classes are analogous to virtual procedures. Virtual classes are mainly interesting within strongly typed languages where they provide a mechanism for defining general parameterized classes such as set, vector and list. In this sense they provide an alternative to generics. Although the notion of virtual class originates from BETA, it is presented as a general language mechanism.</p>

scholarly journals Static Typing for Object-Oriented Programming

1991 ◽  
Vol 20 (355) ◽  
Author(s):  
Jens Palsberg ◽  
Michael I. Schwartzbach
Keyword(s):  
Partial Order ◽  
Object Oriented ◽  
Object Oriented Programming ◽  
Finite Sets ◽  
Object Oriented Languages ◽  
Static Typing

We develop a theory of statically typed object-oriented languages. It represents classes as labeled, regular trees, types as finite sets of classes, and subclassing as a partial order on trees. We show that our subclassing order strictly generalizes inheritance, and that a novel genericity mechanism arises as an order-theoretic complement. This mechanism, called class substitution, is pragmatically useful and can be implemented efficiently.

scholarly journals Substitution Polymorphism for Object-Oriented Programming

1990 ◽  
Vol 19 (305) ◽  
Author(s):  
Jens Palsberg ◽  
Michael I. Schwartzbach
Keyword(s):  
Type System ◽  
Object Oriented ◽  
Object Oriented Programming ◽  
The Novel ◽  
Type Checking ◽  
Generic Class ◽  
Object Oriented Languages

We introduce substitution polymorphism as a new basis for typed object-oriented languages. While avoiding subtypes and polymorphic types, this mechanism enables optimal static type-checking of generic classes and polymorphic functions. The novel idea is to view a class as having a family of implicit subclasses, each of which is obtained through a substitution of types. This allows instantiation of a generic class to be merely subclassing and resolves the problems in the <em> Eiffel</em> type system reported by Cook. All subclasses, including the implicit ones, can reuse the code implementing their superclass.

scholarly journals A Unified Type System for Object-Oriented Programming

1990 ◽  
Vol 19 (341) ◽  
Author(s):  
Jens Palsberg ◽  
Michael I. Schwartzbach
Keyword(s):  
Type System ◽  
Object Oriented ◽  
Type Systems ◽  
Object Oriented Programming ◽  
Type Checking ◽  
Separate Compilation ◽  
Set Inclusion ◽  
New Type ◽  
Efficient Type ◽  
Object Oriented Languages

We present a new type system for object-oriented languages with assignments. Types are sets of classes, subtyping is set inclusion, and genericity is class substitution. The type system enables separate compilation, and unifies, generalizes, and simplifies the type systems underlying SIMULA/BETA, C++, EIFFEL, and Typed Smalltalk, and the type system with type substitutions proposed by Palsberg and Schwartzbach, Classes and types are both modeled as node-labeled, ordered regular trees; this allows an efficient type-checking algorithm.

Proper Placement of Derived Classes in the Class Hierarchy

2005 ◽  
pp. 486-492
Author(s):  
Reda Alhajj ◽  
Faruk Polat
Keyword(s):  
Object Oriented ◽  
Homogeneous System ◽  
Class Hierarchy ◽  
Virtual Class ◽  
Virtual Classes ◽  
Class Definition ◽  
Current Database

Users may derive new classes by defining views1 based on the current database contents. Some virtual classes are classified as brothers of existing classes, and others are either superclasses or subclasses of existing base and virtual classes. A base class is defined directly by the user using class definition constructs. A virtual class is classified as a brother of another class if it is derived from the latter class via a selection. To have a homogeneous system, virtual classes must be treated as first-class citizens in an object-oriented model.

Computer-Aided Design of Mechatronic Systems Using Multiobjective Optimization and Object-Oriented Languages

2012 ◽  
Author(s):  
Didier Casner ◽  
Jean Renaud ◽  
Dominique Knittel
Keyword(s):  
Computer Aided Design ◽  
Multidisciplinary Design Optimization ◽  
Object Oriented ◽  
Object Oriented Programming ◽  
Multidisciplinary Design ◽  
Modeling Language ◽  
Mechatronic Systems ◽  
Aided Design ◽  
Object Oriented Languages ◽  
Oriented Programming Language

This paper deals with the fast modeling and fast multiobjective optimal design of mechatronic systems. To solve this problem, the object-oriented modeling language Modelica and object-oriented programming language Java have been used to build an innovate software platform. This platform has been designed to allow multidisciplinary design optimization of complex systems using a free platform. This platform only contains open-source tools and frameworks and was validated on an optimization application: the stabilization of a quarter-car system.

scholarly journals Family Genericity

2006 ◽  
Vol 35 (578) ◽  
Author(s):  
Erik Ernst
Keyword(s):  
Object Oriented ◽  
Language Design ◽  
Design Philosophy ◽  
Extension Mechanism ◽  
Precise Knowledge ◽  
Virtual Classes ◽  
Good Support ◽  
Object Oriented Languages

Type abstraction in object-oriented languages embody two techniques, each with its own strenghts and weaknesses. The first technique is extension, yielding abstraction mechanisms with good support for gradual specification.<br />The prime example is inheritance. The second technique is functional abstraction, yielding more precise knowledge about the outcome. The prime example is type parameterized classes. This paper argues that these techniques should be<br />clearly separated to work optimally, and also that current languages fail to do this.We have applied this design philosophy to a language based on an extension mechanism, namely virtual classes. As a result, some elements based on functional abstraction have been introduced, but they are simple and only used for things where they excel; conversely, the virtual classes have become more flexible, because their role is now more well-defined.We designate the result as family genericity. The presented language design has been implemented.

Mutation Testing Applied to Object-Oriented Languages

2018 ◽  
pp. 7459-7469
Author(s):  
Pedro Delgado-Pérez ◽  
Inmaculada Medina-Bulo ◽  
Juan José Domínguez-Jiménez
Keyword(s):  
Programming Languages ◽  
Object Oriented ◽  
Mutation Testing ◽  
Object Oriented Programming ◽  
Mutation Operators ◽  
Current State ◽  
Suitable Technique ◽  
Test Suites ◽  
Object Oriented Languages

Mutation testing is a suitable technique to determine the quality of test suites designed for a certain program. The set of mutation operators and the overall technique should be developed around each programming language in particular. The structures related to the object-oriented paradigm require a tailored analysis addressing them. However, class mutation operators for these languages have not been analyzed at the same extent as traditional operators for procedural languages in the literature. The purpose of the chapter is to look in depth at the development and the current state of mutation testing, and more specifically, with regard to object-oriented programming languages.

Mutation Testing Applied to Object-Oriented Languages

2019 ◽  
pp. 1426-1438
Author(s):  
Pedro Delgado-Pérez ◽  
Inmaculada Medina-Bulo ◽  
Juan José Domínguez-Jiménez
Keyword(s):  
Programming Languages ◽  
Object Oriented ◽  
Mutation Testing ◽  
Object Oriented Programming ◽  
Mutation Operators ◽  
Current State ◽  
Suitable Technique ◽  
Test Suites ◽  
Object Oriented Languages

Mutation testing is a suitable technique to determine the quality of test suites designed for a certain program. The set of mutation operators and the overall technique should be developed around each programming language in particular. The structures related to the object-oriented paradigm require a tailored analysis addressing them. However, class mutation operators for these languages have not been analyzed at the same extent as traditional operators for procedural languages in the literature. The purpose of the chapter is to look in depth at the development and the current state of mutation testing, and more specifically, with regard to object-oriented programming languages.

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