AutoLISP

AutoLISP is a dialect of the programming language Lisp built specifically for use with the full version of AutoCAD and its derivatives, which include AutoCAD Civil 3D, AutoCAD Map 3D, AutoCAD Architecture and AutoCAD Mechanical. Neither the application programming interface (API) nor the interpreter to execute AutoLISP code is included in the AutoCAD LT product line (up to Release 2023, AutoCAD LT 2024 includes AutoLISP). A subset of AutoLISP functions is included in the browser-based AutoCAD web app.

==Features== AutoLISP is a small, dynamically scoped, dynamically typed Lisp language dialect with garbage collection, immutable list structure, and settable symbols, lacking in such regular Lisp features as macro system, records definition facilities, arrays, functions with variable number of arguments and let bindings. Aside from the core language, most of the primitive functions are for geometry, accessing AutoCAD's internal DWG database, or manipulation of graphical entities in AutoCAD. The properties of these graphical entities are revealed to AutoLISP as association lists in which values are paired with AutoCAD group codes that indicate properties such as definitional points, radii, colors, layers, linetypes, etc. AutoCAD loads AutoLISP code from .LSP files.