插件介绍

优点

AutoCAD插件的优点：

使添加新特性变得简单
允许第三方开发者开发新特性
给予用户自由定制特性

插件文件格式

.fas：由AutoLISP创建的AutoLISP已编译文件。FAS文件只包含单个编译过的AutoLISP函数。

.vlx：由AutoLISP创建的AutoLISP已编译文件。VLX文件包含多个编译过的AutoLISP函数。

.lsp：AutoLISP源代码文件，该文件由ASCII编码格式保存。

FAS文件和VLX文件的区别

从语义上理解，, 一个函数只包含一个功能，FAS只能包含一个AutoLISP函数，那么FAS文件提供的功能是单一的，只能作为单一目的的插件使用。

VLX文件是独立的AutoCAD应用程序，可以包含多个AutoLISP函数（可能存在个别函数是从FAS文件引入的），因此VLX文件的功能更多样，更强大，可以作为正式的插件使用。

References

Here is a brief summary of the types of files used by the VLISP project management feature:

Visual LISP project file types

File ext.	Type of file	Function
.fas	Compiled AutoLISP code	Compiled AutoLISP programs. May be loaded and run, or compiled into VLX modules
.lsp	AutoLISP source code	Program source files
.ob	Object code	Used internally by VLISP, these files contain compiled AutoLISP code used in building FAS files
.pdb	Project database	Used internally by VLISP, these files contain symbol information used by the compiler
.prj	Project definition	Contains the location and names of all source files that build the project, as well as certain parameters and rules on how to create the final FAS files

In addition to the files recognized by the project manager, VLISP either creates, processes, or recognizes a number of additional types of files, as summarized below:

Additional Visual LISP file types

File ext.	Type of file	Function
.dsk	Desktop save	Contains VLISP environment and window settings. (Note: Editing this file may permanently change the VLISP environment. Do not edit this file without creating a backup copy first.)
._xx	Backup files	Backup copies of edited files, maintained by the VLISP editor. Backup files contain the same name as the original, except that the file extension begins with the underline character (_) and is followed by the first two characters of the original file’s extension. For example, the backup file of a LSP file has an ._LS extension; the backup of a DCL file has a ._DC extension.
.vlx	Stand-alone applications	Stand-alone AutoCAD applications, which can be created using the VLISP Make Application wizard.
.c, .cpp, .cch, .hpp, .hh	Language source files	Contain program source code. The VLISP editor recognizes the syntax of these files and color-codes reserved words, strings, and numbers.
.dcl	Dialog control language	Contains definitions of AutoCAD dialog boxes. VLISP can preview these files, and you can include them in Visual LISP executable (VLX) files.
.prv	Make application	Defines the files and options used to build a VLX application with the VLISP Make Application wizard.
.sql	Structured query language	Contains SQL statements. The VLISP text editor recognizes this file type and color-codes the text according to SQL syntax rules.