Load and run basic LISP (or "AutoLISP") routines. Click the LISP tab on the left sidebar, then click Manage LISP to access the Support Files manager and upload LISP files. Load LISP routines into the drawing, and choose which LISP routines should run at startup, meaning every time you open a drawing.
LISP is an application interface for automating of design tasks. When a LISP application is loaded, it functions in its own namespace for each drawing that is open. A namespace is an insulated environment keeping LISP applications that are specific to one drawing from having symbol or variable name and value conflicts with those in another drawing. For example, the following line of code sets a different value to a symbol when executed in each open drawing.
(setq a (getvar "DWGNAME"))
LISP applications can prompt the user for input, access built-in AutoCAD commands directly, and modify or create objects directly in the drawing database. By creating LISP routines, you can add discipline-specific or workflow driven commands to AutoCAD. Some of the standard AutoCAD commands are actually LISP applications.
You may choose to experiment by entering code at the Command prompt, which allows you to see the results immediately. This makes LISP an easy language to experiment with, regardless of your programming experience.
Even if you are not interested in writing LISP applications, the program includes many useful routines. LISP applications are also available for download from the Internet or third-party developers. Knowing how to load and use these routines can enhance your productivity.