ALS Prolog

ALS Prolog is a Prolog compiler and development environment, available for most desktop platforms. ALS Prolog is a project of Applied Logic Systems, Inc. It is an open source version of the original commercial ALS Prolog active in the 1980-90’s.

Source code is maintained in the ALS Prolog Github repository, under the ALS organization.

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Install with Homebrew/Linuxbrew Formula

Browse the Documentation

☆ Current Status of ALS Prolog

Command-line and GUI versions are available for modern Macintosh, Linux, and Windows systems.

The initial release of the open source ALS Prolog can be characterized as a “minimal viable open source prolog”. It is a 32-bit system, and provides most everything expected in a prolog TTY shell. The GUI shell is based on Tcl/Tk, and provides a basic core, including a console and visual editor windows supporting source trace debugging. A partially complete project-oriented subsystem is present; several repository Issues indicate directions for its completion.