HCSW Forth Internals Handbook
HCSW Forth Internals Handbook

This is a work in progress of a book I am in the process of writing. Please bear with me while I get the content written, proofread the pages, and debug the forth code. Feel free to pass along any suggestions/comments to me here.

Forth is a beautiful language. It is beautiful because of its flexibility, extensibility, and simplicity. The largest barrier to forth programming is, however, learning how the language's internals work. In languages such as C, there is a large semantic gap between the programmer and the language. In many cases this is convenient and sometimes even highly desirable, but there are many instances when having complete understanding and control over a language can offer many very distinct advantages.

There are many tutorials and HOWTOs online about getting started with forth, but it is difficult to find a comprehensive resource on the internals of the forth language. I believe this is essential for proper programming in forth. This ignorance of the scope and applicability of forth is, in my opinion, one of the most frequent sources of misunderstanding regarding the language.

I attempt to explain the internals of the forth language in this handbook. It is assumed that the reader is vaguely familiar with forth usage. In particular, it is assumed the reader has grasped the basics of manipulating the stack and defining words. Advanced users will probably find the topics in Basic Forth Internals familiar and perhaps somewhat tedious, but even the most advanced users will probably gain a small piece of insight from the Advanced Forth Internals section. Even if it is just re-stating concepts in a manner you may not have thought of, this handbook should have something to offer you.

Basic Forth Internals

Advanced Forth Internals

Forth Examples



All content is (C) Doug Hoyte, hcsw.org, and/or its respective owner.