CAD-Admin.com - AutoLISP

AutoLISP

General basics of AutoLlSP which are the building blocks for all of it

While there are now more modern programming methods for AutoCAD such as .NET, I prefer to use Autol_lSP, but not VisualLlSP when I can help it. AutoLlSp will always work in any version whether its newer or older.

Even if you have never programmed, AutoLlSP is simply a set of mostly linear instructions. They can sometimes reference other instructions but then return to where the previous instruction left off. It can be a gateway to more modern programming languages or other CAD specific programming languages such as PML.

Anything which can be picked within the drawing area or typed at the command line can be strung together into a single command which runs through it all for you.

How to start

How to begin making an AutoLISP routine

Write down the steps

Write down the exact steps you would use in AutoCAD
- Everything typed on the command line
- Everything picked within the drawing area.

Create a new .1sp file

Launch VLIDE editor from within AutoCAD
- Create a new .1sp file

Update the header

- Date
- Your name
- Purpose:
- The list you wrote down

Start the code

Add the root C:defun code
Start translating each step above into AutoLlSP code
Push code from VLIDE to AutoCAD to test and troubleshoot

Add it to a ribbon menu for regulat use

Adding Comment(s)

One or more semicolon (;) is used to comment or remark within code which won't be used as part of the program sequence.

;Comment
;;;Comment
<code> ;comment
<code> ;;;COMMENT

DEFUN

A defun can be either a command typed at the command line or manually called from the command prompt or from another routine.

Adding a C: in front of the defun name will make it available to type at the command line. Without that, it must be called by using (defun mane)

(defun C:ProgramName ( / )

);end defun

Variables

There are two types of variables. Those only used locally for the routine, and those which will be kept active for other programs to see/use.

(defun C:ProgramName (PARAMETER1 PARAMETER2 / LOCAL1 LOCAL2)

PARAMETER* - A defun can be fed parameters which are used within the routine. For example (TEST 0.25 "BOLT") runs the TEST defun but prepares to use the two fed values as PARAMETERI and 2.

LOCAL* = Any variable names after the / will automatically be set to nil upon completion of the defun routine. Any variables not included here will keep its value and can be referenced by other routines run afterwards. It is good housekeeping to clear these values if they won't be used later