Preface

4D has its own programming language. This built-in language, consisting of more than 1000 commands, makes 4D a powerful development tool for database applications on desktop computers. You can use the 4D language for many different tasks—from performing simple calculations to creating complex custom user interfaces. For example, you can:

• Programmatically access any of the record management editors (order by, query, and so on),
• Create and print complex reports and labels with the information from the database,
• Communicate with other devices,
• Manage documents,
• Import and export data between 4D databases and other applications,
• Incorporate procedures written in other languages into the 4D programming language.

The flexibility and power of the 4D programming language make it the ideal tool for all levels of users and developers to accomplish a complete range of information management tasks. Novice users can quickly perform calculations. Experienced users without programming experience can customize their databases. Experienced developers can use this powerful programming language to add sophisticated features and capabilities to their databases, including file transfer and communications. Developers with programming experience in other languages can add their own commands to the 4D language.

The 4D programming language is expanded when any of the 4D modules are added to the application. Each module includes language commands that are specific to the capabilities they provide.

The manuals described here provide a guide to the features of both 4D and 4D Server. The only exception is the 4D Server Reference, which describes features exclusive to 4D Server.

• The Language Reference is a guide to using the 4D language. Use this manual to learn how to customize your database by incorporating 4D commands and functions.
• The Design Reference provides detailed descriptions of the editors and tools available in this environment.
• The Self-training manual leads you through example lessons in which you create and use a 4D database. These examples provide hands-on experience and help you become familiar with the concepts and features of 4D and 4D Server.
• The 4D Server Reference, which is included only in the 4D Server package, is a guide to managing multi-user databases with 4D Server.

This manual describes the 4D language. It assumes that you are familiar with terms such as table, field, and form. Before you read this manual, you should:

• Use the Self-training manual to work through the database example.
• Begin creating your own databases, referring to the Design Reference manual when necessary.
• Increase your knowledge by studying that numerous demo and example databases that are available on the 4D Web site (http://www.4d.com).

In this manual, several writing conventions are used:

• Following the example of the 4D Method editor, commands are written in all caps using special characters, e.g.: CLOSE DOCUMENT. Functions (commands that return a value) start with a capital letter and continue in lower case, e.g.: Change string.
• In the command syntax, the { } characters (braces) indicate optional parameters. For example, SET DEFAULT CENTURY (century{; pivotYear}) means that the pivotYear parameter may be omitted when calling the command.
• In the command syntax, the | character indicates an alternative. For example, Table (tableNum | aPtr) indicates that the function accepts either a table number or a pointer as parameter.
• In certain examples in this documentation, a line of code may be continued onto the following line(s) due to lack of space. However, you should type these examples as a single line of code without using carriage returns.

If you are reading this manual for the first time, read the Introduction section.