Welcome!

About the Forth Programming Language

The Forth programming language was originally developed in the early 1970s by Charles H. Moore, at the National Radio Astronomy Observatory. Forth was used at several NRAO installations for controlling radio telescopes and associated scientific instruments, as well as for high-speed data acquisition and graphical analysis. Today Forth is used worldwide by people seeking maximum flexibility and efficiency in a wide variety of application areas.

About This Book

The Forth Programmer’s Handbook book provides a detailed technical reference for programmers and engineers who are developing software using versions of Standard Forth (ANSI X3.215:1994, the standard adopted in 1994; equivalent to ISO/IEC 15145:1997) provided by FORTH, Inc. or other vendors. It features Standard Forth and many extensions commonly in use; some information in this book is taken directly from the official standard’s documentation.

This book assumes the reader has a general knowledge of programming principles and practices, and general familiarity with computer hardware and software systems.

How to Use This Book

Each section of this book documents a single subject, and many are followed by a glossary containing pertinent Forth words and their descriptions. Each

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Forth Programmer’s Handbook

Forth word is shown with its stack effects and with the Standard Forth word list in which it appears, if any. Some words are included which are not part of Standard Forth; these are indicated by the phrase “common usage.” Sections in this book often conclude with references to related topics or other resources.

Appendix C provides an index of each Forth word that appears in these glossaries, including its stack effect, the page on which its description may be found, and the Standard Forth word list, if any, in which it appears.

Reference Materials

The following reference materials may be of use to the reader of this manual.

!Starting Forth (introductory tutorial).

!American National Standard for Information Systems Programming Languages Forth (ANSI X3.215:1994)

!ISO/IEC 15145:1997 Information technology Programming languages Forth

(the content of this standard is identical to ANSI X3.215:1994)

Additional recommended publications are listed in Appendix A, “Bibliography” on page 201, along with other sources of information about Forth.

How to Proceed

If you are not already familiar with Forth, we encourage you to begin by reading the ”Introduction” and ”Forth Fundamentals” chapters carefully, writing simple programs using an ANS Forth system of your choice. Use this book for technical details about your standard-compliant system and to assist you as you move on to more ambitious programming challenges.

Good luck!

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