Progress
Language Tutorial
for Windows


About the Application Development Language

Most general-use programming languages—such as COBOL, FORTRAN, and BASIC—are called third generation languages (3GLs). These languages let you control a computer at a low level, while using an English-like syntax that makes the resulting code understandable.

The Progress application development language is a fourth generation language (4GL). A 4GL makes programming much easier because it:

Besides giving you the complete flexibility of a general-use programming language, the Progress 4GL allows you to do two main tasks: access and manipulate data in a database, and present that data for user inspection and interaction.

Look at this Progress code:

FOR EACH Customer:
  DISPLAY Customer.
END. 

This compact loop, where Customer is the name of a database table, performs these functions:

Each of these tasks would require many lines of 3GL code. The Progress 4GL executes these tasks implicitly.

Progress also makes useful assumptions about what you want, relieving you from the tedious task of coding every tiny detail. For example, notice that the DISPLAY statement in the example does not offer any detail about how to format the output. Progress constructs a default output format by combining default formatting information for each database field with default output algorithms. This intuitive handling of defaults is called default behavior. This advantage does not come at the expense of customization. Every Progress statement includes options that allow you to override default behavior.

You’ll find yourself relying on default behavior in the beginning of a project so that you can quickly create a prototype. Later, you’ll get more involved with programming options to fine tune your application.


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