Chapter 1: Introduction to IBM Smalltalk Programming

Smalltalk Development Enviroment
VisualAge and IBM Smalltalk

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Smalltalk Development Enviroment

IBM Smalltalk is a complete development enviroment for implementing object-oriented applications. Smalltalk is a pure object-oriented model which means that everything in the enviroment is treated as an object. Among object-oriented languages, Smalltalk is the most consistent with handling the definitions and properties of the object-oriented paradigm as described in the "Object-Oriented Paradigm" section.

Smalltalk is more than just a language, it is an extensive program development enviroment with over two hundred classes and several thousand methods. Smalltalk consists of the following components:

A language: IBM Smalltalk supports the Smalltalk language. Because everything in Smalltalk is an object, the language is lean.
An object model from which objects are defined: The object model defines how objects behave. The object model supports inheritance, class and instance behavior, dynamic binding, messaging, and garbage collection.
A set of reusable classes: Smalltalk has abundant of classes that can be reused in any Smalltalk program. These classes provide the basic functions in Smalltalk plus additional support for cross-platform portability, including protable graphical user interfaces, and support for the definition and management of classes.
A set of development tools: These tools enable users to look at and modify existing classes, rename classes, add new classes, and delete classes. They also provide source-level debugging, including the ability to add halts, look at data, modify data, and make changes to code during the exercution of a program.
A runtime enviroment: Smalltalk allows users to break out of the "compile-link-run" cycle. The editor, compiler, linker, debugger and the application in Smalltalk are part of the runtime image. This allowed users to run the smalltalk program while changing the source code. Changes made to the source code are reflected in the running application instantly.

                                 

 
                            
          Tools                  Reusable Classes
   ST Execution
Object model                         Runtime support                           
                                                                       
                     Language

One of the greatest features of Smalltalk is its high degree of reusability. Smalltalk comes with a rich set of objects that can be used directly or easily modified to fit a particular application's needs. Objects often can be used in more than one application. This results in improved productivity and quality in the workplace.

VisualAge and IBM Smalltalk

IBM has several Smalltalk development products, such as VisualAge and IBM Smalltalk. VisualAge emphasizes on visual construction of interfaces and applications while IBM Smalltalk emphasizes on more traditional textual programming approach. Both enviroments come with two levels of development support: team and individual. Both run on several platforms including IBM OS/2, Microsoft Windows, and AIX.

IBM Smalltalk programs look, feel, and act though they were actually in their development enviroment. An IBM Smalltalk application written for windows looks like a windows application. Each product's look varies from one implementation platform to another. This tutorial concentrates on the language which is common to and uniform across all IBM products and platform.

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Smalltalk Tutorial

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