Smalltalk-80: the language and its implementation
Smalltalk-80: the language and its implementation
Programming in Modula-2
What does Modular-2 need to fully support object oriented programming?
ACM SIGPLAN Notices
| Hi-index | 0.01 |
Software systems represent a hierarchy of modules. Client modules contain sets of procedures that extend the capabilities of imported modules. This concept of extension is here applied to data types. Extended types are related to their ancestor in terms of a set hierarchy. Variables of an extended type form a subset of the variables of the ancestor type. This scheme is easily and efficiently implementable, and is manifest by two new language constructs only: the type test and the type guard.