Chapter 1: Introduction to IBM Smalltalk Programming
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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:
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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.
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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.
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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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