论文部分内容阅读
ＥＸＰＲＥＳＳ是ＳＴＥＰ资源和应用协议的定义基础。本文主要介绍ＥＸＰＲＥＳＳ语言比较特殊的类和对象特征：子类和超类，属性和规则的继承以及子类超类约束关系
EXPRESS is the defining basis for STEP resources and application protocols. This article describes the EXPRESS language is relatively special classes and object features: subclasses and superclasses, inheritance of attributes and rules, as well as superclass constraint subclasses