Atlast is an attempt to make software component technology and open architecture applications commonplace in the mainstream software market. It is both a software component which can be readily integrated into existing applications, providing them a ready-made macro language and facilities for user extension and customisation and, at the same time, a foundation upon which new applications can be built in an open, component-oriented manner.

Atlast was developed at Autodesk, Inc. Autodesk returned the rights to me in 1991, and I subsequently placed the program in the public domain. Autodesk's connection with this program is purely historical: it is neither endorsed, used, nor supported by Autodesk, Inc. This edition of Atlast, including a native 64-bit implementation and a 32-bit version which can be run either on a 32-bit system or cross-compiled for a 64-bit system, is released under the Creative Commons CC-SA license as described in the file LICENSE.md.

Atlast is based upon the FORTH-83 language, but has been extended in many ways and modified to better serve its mission as an embedded toolkit for open, programmable applications. Atlast is implemented in a single file, written in portable C; it has been ported to many different machines and operating systems, including MS-DOS, OS/2, the Macintosh, and a wide variety of Unix machines. Atlast includes native support for floating point, C-like strings, Unix-compatible file access, and a wide variety of facilities for embedding within applications. Integers are 32 bits (64 bits in the 64-bit version of Atlast) and identifiers can be up to 127 characters; extensive stack and heap pointer checking is available to aid in debugging. Atlast may be configured at compilation time to include only the facilities needed by a given application, thus saving memory and increasing execution speed (when error checking is disabled).

Atlast is available in either the original 32-bit version, maintained in the atlast-32 directory, or in a native 64-bit version, in the atlast-64 directory. Because Atlast, like all FORTH-like languages, provides low-level access to system memory, these two versions are not source code compatible: in particular, in the 64-bit version integers, pointers, and floating point numbers are all 64 bits in length and may be manipulated by the same stack commands, while in the 32 bit version floating point numbers occupy two adjacent 32 bit words and a set of double word operators are used with them.

If you are confident the code you're developing will always run on 64-bit platforms, the 64-bit version is generally faster, easier to program, and directly compatible with system libraries. The 32-bit version may be used on 64-bit platforms as long as a compiler able to cross-compile to 32-bit code and the necessary compatibility libraries are installed on the systems used to develop and deploy applications.

Due to language differences between the 32- and 64-bit versions of Atlast, each has its own documentation.

• Atlast 32-bit
• Atlast 64-bit