Lisa is a modern, production-quality expert-system shell built on the principles of Common Lisp, leveraging the optimized Rete algorithm for efficient reasoning. Designed for seamless integration with existing Common Lisp applications, Lisa maximizes the potential of the Common Lisp Object System (CLOS) and the Meta Object Protocol (MOP) without enforcing strict class hierarchy limitations. This flexibility allows developers to enhance their applications with sophisticated reasoning abilities effortlessly.

Key Features

• Efficient Reasoning Engine: Employs an optimized implementation of the Rete algorithm to tackle complex many-to-many matching problems.
• CLOS Integration: Integrates smoothly with CLOS objects, allowing for the extension of existing applications with reasoning capabilities.
• Cross-Platform Compatibility: Fully compatible with any ANSI-compliant Common Lisp platform, ensuring a broad scope of functionality across various systems.

Supported Lisp Implementations

Lisa has been tested and confirmed to operate on:

• SBCL
• LispWorks
• Allegro Common Lisp (ACL)
• CLISP
• CMUCL
• OpenMCL
• Armed Bear Common Lisp (ABCL)

Ongoing Development

As of December 2024, Lisa has transitioned from SourceForge to GitHub with significant updates, including bug fixes and new features such as logging support through log4cl. This version has undergone extensive profiling to optimize performance. Future plans include integration with Quicklisp and enhancements based on user feedback and testing.

Documentation and Examples

For complete usage details, including practical examples of classic AI problems solvable with Lisa, refer to the Lisa Wiki and the example rulebases documented here.

Existing capabilities are complemented by an active community and exemplary contributions, acknowledging the inputs of developers like gassechen and cdmojoli.

Lisa stands as a robust tool for developers seeking to incorporate expert reasoning capabilities into their Lisp applications.