Abstract

Design and programming are important stages of the development process of object-oriented information systems. At the design stage, a problem domain model is built, usually in the form of a UML class diagram. Sometimes it is convenient for a designer to apply the concept of metaclass to model the problem domain. However, UML does not directly support metaclasses. It is described how in some cases it is possible to move from models with metaclasses to models with standard classes. Examples are given showing the capabilities of Python, Scala, and Objective-C for implementing such models. In addition, an analysis of differences in the interpretation of the concept of metaclass in these languages is carried out.

中文翻译：

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UML 和编程语言中的元类

摘要

设计和编程是面向对象信息系统开发过程的重要阶段。在设计阶段，建立问题域模型，通常采用 UML 类图的形式。有时，设计者应用元类的概念来对问题域进行建模是很方便的。然而，UML 并不直接支持元类。描述了在某些情况下如何可以从具有元类的模型转移到具有标准类的模型。给出的示例展示了 Python、Scala 和 Objective-C 实现此类模型的功能。此外，还对这些语言中元类概念的解释差异进行了分析。