Allegro Common Lisp
Allegro CL is a dynamic object-oriented development environment for Common Lisp/CLOS that is ideal for complex, mission-critical projects, where flexibility, scalability, and speed are essential.
Allegro CL's dynamic objects technology makes it possible to create applications that can be updated or changed while the application is running. An object-oriented programming system designed to provide cross-platform portability, it enables you to build highly scalable, evolved systems for deployment on a wide range of Unix systems and Windows. Allegro CL has dynamic runtime behavior, including incremental compilation, automatic memory management, and macro expansion. Applications built in Allegro CL can include domain-specific extensions and are able to evolve and change while running, even without source code.