Three different approaches to type checking have been taken in object-oriented programming languages. Smalltalk-80 uses run-time type checking. C++ uses subtypes. A third alternative is to use parameterized types. We examine the difficulties of programming in an object-oriented fashion with compile-time type checking and argue that parameterized types are better...
Using Smalltalk-80, programmers can produce prototypes much faster than with C or Pascal. What techniques do Smalltalk-80 programmers use to produce these prototypes? What is special about Smalltalk-80 that enables them to uses these techniques? Can these techniques be used with conventional languages such as C? In an attempt to...
Several years ago we began development of an object-based programming language and environment which we call X2. We implemented X2 using a virtual machine similar to Smalltalk-80 implementations, but X2 does no message look-up. The implementation differs from most Smalltalk-80 systems in that objects are paged and in the ability...
The term object-oriented is defined. This definition is then related to message-passing, inheritance, polymorphism, data abstraction, generics, and overloading.
Smalltalk-80 obtains some of its expressive power from arranging classes in a hierarchy. Inheritance is an important aspect of this hierarchy. An alternative organization of classes is proposed that emphasizes description instead of inheritance. This alternative can be used with compile-time type checking and retains the important characteristics of Smalltalk's...
A method for implementing parameterized types is given. Two simplifying restrictions are assumed: types are only parameterized with other types, and assignment is like that of SNOBOL, CLU, and Smalltalk. An algorithm for type checking that handles parameterized types and overloading is presented .
The design of an experimental object-based programming language is discussed. The language is intended for investigating techniques for organization of programs.
Castle Rocks is 12 miles east of Mt. Jefferson, in the central
Cascades of Oregon. The area contains volcanic rocks ranging from
mid-Miocene to Holocene in age. These rocks record alternating
periods of tholeiitic and calc-alkaline volcanism.
The oldest rocks in the area range from basaltic andesite lava
flows to...
Full Text:
north end of Green Ridge, Jefferson County, Oregon
AN ABSTRACT OF THE THESIS OF
DavidW. Wendland