For years, AutoLISP. has set the standard for customizing AutoCAD.. Now Visual LISP. (VLISP) represents the next generation of LISP for AutoCAD, by adding significantly more capabilities. VLISP extends the language to interface with objects via the Microsoft ActiveX. Automation interface, and enhances the ability of AutoLISP to respond to events through the implementation of reactor functions. As a development tool, VLISP provides a complete, integrated development environment (IDE) that includes a compiler, debugger, and other tools to increase productivity when customizing AutoCAD.