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Learn about Smalltalk, Alan Kay, and Xerox PARC's Dynabook, and how Smalltalk provides a Windows-oriented display, an interactive language with point and click or dialogue interfaces, and powerful features like objects, classes, and message passing.
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CSE3302Programming Languages(new notes) Dr. Carter Tiernan Programming Languages
Object-Oriented Programming • Rich interactive environment • Graphics • Sound • Simulation tasks Programming Languages
Smalltalk • Alan Kay • Xerox PARC - Dynabook • Windows-oriented display • Interactive language • Point and click or dialogue • Objects and classes Programming Languages
Structural Organization • Objects have a behavior • Objects can be made to do things by sending them messages • Repetitive operations can be simplified by using control structures Programming Languages
Objects and Classes • Objects are instantiated • Classes are defined • Operators are overloaded implicitly • Methods work with any object matching protocol • Hierarchical classes • Only single inheritance • Names are not typed - dynamic type checking Programming Languages
Messages • Message passing is like procedure invocation • Three message forms • Parameters with keywords and colons • No parameters • Arithmetic • Supports concurrency Programming Languages
Smalltalk • Small and regular language • Windows! • Integrated programming environment • Simulation • Objects to model real-world elements • Classification of objects • Interaction through messages Programming Languages