Virtual classes and nested classes are distinguishing features of BETA. Nested classes originated from Simula, but until recently they have not been part of main stream object-oriented languages. C++ has a restricted ...
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Virtual classes and nested classes are distinguishing features of BETA. Nested classes originated from Simula, but until recently they have not been part of main stream object-oriented languages. C++ has a restricted form of nested classes and they were included in Java 1.1. Virtual classes is the BETA mechanism for expressing generic classes and virtual classes is an alternative to parameterized classes. There has recently been an increasing interest in virtual classes and a number of proposals for adding virtual classes to other languages, extending virtual classes, and unifying virtual classes and parameterized classes have been made. Although virtual classes and nested classes have been used in BETA for more than a decade, their implementation has not been published. The purpose of this paper is to contribute to the understanding of virtual classes and nested classes by presenting the central elements of the semantic analysis used in the Mjolner BETA compiler.
We show how a collection of object-oriented concepts can be directly expressed in predicative programming 6.. We demonstrate how these feature scan be used in cooperation with the existing real-time and concurrency fe...
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Generic types in programming languages are most often supported with various forms of parametric polymorphism, i.e. functions on types. Within the framework of object-oriented languages, virtual types present an alter...
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Discusses the estimation of the effort needed to update programs according to a given requirement change. In object-oriented prototyping development (OO prototyping), the requirement changes occur frequently and regul...
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The proceedings contains 26 papers from the conference on Technology of object-oriented Languages and Systems - Tools 32. The topics discussed include: software architectures;graphical user interfaces;multiple domain ...
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The proceedings contains 26 papers from the conference on Technology of object-oriented Languages and Systems - Tools 32. The topics discussed include: software architectures;graphical user interfaces;multiple domain objects;model-view controllers;embedded real-time systems;object-oriented languages;unified modelling languages;external iterators;distributed systems;databases and multiagent systems.
Abadi and Cardelli [1] present a series of type systems for their object calculi, four of which are first-order. Palsberg [22] has shown how typability in each one of these systems can be decided in time O(n(3)) and s...
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Abadi and Cardelli [1] present a series of type systems for their object calculi, four of which are first-order. Palsberg [22] has shown how typability in each one of these systems can be decided in time O(n(3)) and space O(n(2)), where n is the size of an untyped object expression, using an algorithm based on dynamic transitive closure. In this paper we improve each one of the four type inference problems from O(n(3)) to the following time complexities: [GRAPHICS] Furthermore, our algorithms improve the space complexity from O(n(2)) to O(n) in each case. The key ingredient that lets us "beat" the worst-case time and space complexity induced by general dynamic transitive closure or similar algorithmic methods is that object subtyping, in contrast to record subtyping, is invariant: an object type is a subtype of a "shorter" type with a subset of the method names if and only if the common components have equal types. (C) 1999 John Wiley & Sons, Inc.
We present a general framework HM(X) for type systems with constraints. The framework stays in the tradition of the Hindley/Milner type system. Its type system instances are sound under a standard untyped compositiona...
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We present a general framework HM(X) for type systems with constraints. The framework stays in the tradition of the Hindley/Milner type system. Its type system instances are sound under a standard untyped compositional semantics. We can give a generic type inference algorithm for HM(X) so that, under sufficient conditions on X, type inference will always compute the principal type of a term. We discuss instances of the framework that deal with polymorphic records, equational theories, and subtypes. (C) 1999 John Wiley & Sons, Inc.
The use of entropy as a measure of information content has led to its use in measuring the code complexity of functionally developed software products;however, no similar capability exists for evaluating complexities ...
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The use of entropy as a measure of information content has led to its use in measuring the code complexity of functionally developed software products;however, no similar capability exists for evaluating complexities of object-oriented systems using entropy. In this paper a new metric based on entropy as a complexity measure for object-oriented classes is defined and validated using several large commercial object-oriented projects. The metric is computed using information available in class definitions. The new complexity measure of classes is correlated with traditional complexity measures such as McCabe's cyclomatic metric and the number-of-defects metric, both of which were evaluated from the implementation of the methods of the classes. The correlation study used the final versions of the class definitions. The high degree of positive correlation between the entropy-based class definition measure and the traditional measures of class implementation complexity verify that the new entropy measure computed from class definitions can be used as a predictive measure for class implementation complexities provided the class definitions do not change significantly during the implementation. (C) 1999 John Wiley & Sons, Inc.
One key activity in the early phases of software development is the production of accurate, reliable effort estimates for an optimal efficiency of project management. However, producing such estimates relies mainly on...
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One key activity in the early phases of software development is the production of accurate, reliable effort estimates for an optimal efficiency of project management. However, producing such estimates relies mainly on the ability to accurately predict the size of the software product and then to derive from this size the effort needed to develop it. In order to alleviate this estimation, an estimation model based on the Function Point Analysis method is developed.
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