mastering autolisp in 80 minutes

Mastering AutoLISP in 80 MinutesInstructor: Lynn Allen

Course Summary:AutoLISP has been around for a long time and has always separated the AutoCAD green thumbs from the gurus This course begins by debunking some popular rumorsgreen thumbs from the gurus. This course begins by debunking some popular rumors and explores the amount of AutoLISP code used in CAD-dependent industries today. AutoLISP is more powerful, it’s free and it provides users with the ability to create new AutoCAD commands in minutes. This class helps seasoned AutoCAD users enter the world of customization and programming using AutoCAD's native graphical language. p g g g g p g gThe class is designed for intermediate-level AutoCAD users who have never programmed in AutoLISP before.

You have come to the right place ifYou have come to the right place if...

• You know nothing or very little about Visual LispY t t it Vi l Li ti b t• You want to write your own Visual Lisp routines but have no idea where to begin.

• You would like to have better control over your AutoCAD environment

• You tried to “Walk down the Garden Path” but landed in a ditch!

• You do not have a programming background

Objectives

• To lay a firm foundation of the basics of Visual LiLisp.

• Prepare you to write your own Visual Lisp tiroutines

• Start you down the path to official AutoCAD G d ( “N d ”)Gurudom ( or “Nerdom”)

• Teach you some quick and dirty basics of Visual Li (d ’t l k t l !)Lisp (don’t look too close!).

• Discover new ways to torture your coworkers!

Hold on - we have a lot of information to cover in 80 minutes!cover in 80 minutes!

First and Foremost!Don’t let Visual Lisp intimidate you!Don t let Visual Lisp intimidate you!

What does LISP stand for?What does LISP stand for?

LISt ProcessorLISt Processor(not Lost In Stupid(not Lost In Stupid

Parentheses!)

The BasicsThe Basics

• Lists• Functions• Functions• Arguments• Golden Rules of AutoLISP

Wh t i LIST?What is a LIST?

Anything inside of parentheses

Examples of LISTS:Examples of LISTS:(a b c)(setq x 1)(princ)(princ)

What is a FUNCTION?What is a FUNCTION?(or subr)

The ACTION you want Visual Lisp to do!

In Visual Lisp the function ALWAYS go first!!!go first!!!

Visual Lisp uses Prefix notation

Example: (+ 1 2)(- 5 3)(inters A B C D)(setq x 3)

Visual Lisp as a CalculatorVisual Lisp as a CalculatorINFIX Notation(1 + 1)(3 * 4)(3 * 4)(6 / 2)(6 / )PREFIX Notation(+ 1 1)(* 3 4)( 3 4)(/ 6 2)

ArgumentsArguments• Arguments are the values you pass to a

f tifunction(+ 5 6)+ is the function5 and 6 are the argumentsg

(setq x “Autodesk”)(setq x Autodesk )Setq is the functionX and “Autodesk” are theX and Autodesk are the arguments

The Golden Rules of Visual Lisp

• For every open paren, you must have a l dclosed parenExample: (setq x (+ a b))p ( q ( ))

• For every open double quote, you must have a closed double quotehave a closed double quote.Example: (prompt “How are you?”)

The Key to unlocking complicated LISP tiLISP routines:

Visual Lisp works from the Inside Outp(+ 5 (* 4 3))is equal to (4 * 3) + 5( 3) 5(- (+ 5 2) (* 6 (- 7 6)))i l tis equal to(5 + 2) - (6 * (7 - 6))( ) ( ( ))7 - (6 * 1)

Quiz Time!Q

(* 4 (/ (+ 6 3) 3))(* 4 (/ (+ 6 3) 3))1212(+ (* (- 5 2) (/ 15 3)) 6)21(/ (* ( 11 9) ( 25 5)) (* 3 2))(/ (* (- 11 9) (+ 25 5)) (* 3 2))1010

Some popular Data Types:p p yp

• Real Numbers 1.5• Integers 5• Integers 5• Strings “LINE”• Lists (8 . “DIM”)• Subrs (or functions) SETQ• Subrs (or functions) SETQ

Real Numbers and Integers

• Real Numbers have decimal pointsExample: 1.3 5.0

• Integers do not!Example: 25 11

• Real Numbers must have a leading zero.5 is incorrect 0 5 is correct.5 is incorrect 0.5 is correct

D tt d i (0 “CIRCLE”)Dotted pair: (0 . “CIRCLE”)error: misplaced dot on input

(/ 7 2) => 3(/ 7 2) => 3(/ 7 2.0) => 3.5(+ 1 2 3 4 5 6. ) => 21.0(+ 1 5) => invalid dotted pair(+ 1 .5) => invalid dotted pair(+ 1 0.5) => 1.5

One real number changes the entire pot!

Basic Arithmetic Functions (for you math-heads):

+ = addition * = multiplication/ division subtraction/ = division - = subtraction

(sqrt x) (sin ang) (atan x)( t ) ( )(expt x y) (cos ang)(abs x) (log x)( ) ( g )(float x) (fix x)

btwbtw...

Angles are measured in radians!(not degrees)

and you’ll need to remember thatand you’ll need to remember that.

St iStringsUsually Text (literals)Usually Text (literals)Always double-quotedAlways double quotedSpaces accepted

E l “ t d k”Examples: “autodesk”“line”line“1.25”

Setting VariablesSetting Variables(SETQ)

(SETQ X 1)(SETQ X 1)SETQ is the function

X is the variable name1 is the value1 is the value

Setting several variables at once:Setting several variables at once:(SETQ A 1 B 2 C 3)

Variable Names

• Alpha-numeric• May not contain spaces• May not contain spaces• should not replace existing preset values

h T isuch as T or pi

Note: A variable that hasn’t been set isNote: A variable that hasn t been set is equal to nil

Using Visual Lisp variables in AutoCADAutoCAD

(setq X 1 Y 2)

Command: !Xreturns 1C d i lCommand: circle3P/2P/TTR/<Center point>:3P/2P/TTR/ Center point :Diameter/<Radius>:!Y

Ways to ruin your Visual Lisp life

(setq + -)( q )(setq * /)( i )(setq pi 2.5)

Visual Lisp will let you abuseVisual Lisp will let you abuse yourself. . .

Using AutoCAD commandsUsing AutoCAD commands in Visual Lisp (the good stuff!)

Using the COMMAND function, you can th A t CAD daccess the AutoCAD commands

Example:a p e(command “QSAVE”)(command “TRIM”)(command “ZOOM” “P”)(command ZOOM P )(command “LAYER”)

By default, Visual Lisp doesn’t display dialog boxesdisplay dialog boxes

Vi l Li di l th d li i t fVisual Lisp displays the command line interface for commands.

To force the dialog box use:(initdia)

Before the command:

(initdia)(initdia)(command “layer”)

ll f i tpause allow for user input

(command) cancel

“” enter

(Command “ZOOM” “A”)

(C d “ERASE” “L” ““)(Command “ERASE” “L” ““)

(Command “INSERT” “DESK” pause 1 1 pause)(Command INSERT DESK pause 1 1 pause)

(Command “LINE” A B C “C”)( )

(Command “TEXT” pause “.5” 0 “Visual Lisp”)

(Command “LAYER” “S” pause ““)

(Command)

Creating your own AutoCADCreating your own AutoCAD Commands

(DEFUN)DEFUN binds a set of expressions to aDEFUN binds a set of expressions to a

variable.(DEFUN C ZAP ( )(DEFUN C:ZAP ( )

dCommand: zap

Anatomy of DEFUN• DEFUN

i th f ti

ato y o U

is the function• C:C:

indicates the function will be an AutoCAD commandAutoCAD command

• ( )( )indicates no local variables and no arguments (we’ll get to that anotherarguments (we ll get to that another

time!)

DEFUN examplesp

(DEFUN C ZA ( )(DEFUN C:ZA ( )(Command “ZOOM” “A”)

))(DEFUN C:SQ ( )

( d “ ” “ ” )(Command “POLYGON” 4 “E” pause pause))(DEFUN C:ZAP ( )

(Command “erase” “all” ““))

SHORT.LSP(defun c:ls ( )(command “la e ” “M” pa se ““)(command “layer” “M” pause ““)

)(defun c:ZO ( )

(command “ZOOM” “O”))(defun c:ttr ( )( ( )

(command “circle” “ttr” pause pause pause)))(defun c:Jellydonut ( )

(command “donut” “0” pause )(command donut 0 pause ))

Loading Visual Lisp routinesLoading Visual Lisp routines • APPLOAD - used to load one or more VisualAPPLOAD used to load one or more Visual

Lisp routines

• (load “short”)( )

Opening a dialog to a specific tabOpening a dialog to a specific tab

(command “+dialogname” X)

(command “+options” 7)will open the Options dialog to tab #8

(command “+customize” 0)

What’s wrong with this picture?g p

(defun c:door (“insert” “door” pause 1 1 45)( insert door pause 1 1 45)

)(defun c:fun ())

(prompt “are we having fun yet?)(prompt are we having fun yet?))

PPurge.LSPg

(Defun c:ppurge ( )(Defun c:ppurge ( )(command “purge” “all” “*” “N”)

)

Let’s create a command that breaks an object in the samebreaks an object in the same

spot twice

(defun c:crack ()

Clean up your ACT!p y

• PRINC (get rid of the nils!)

PPurge.LSPg

(Defun c:ppurge ( )(Defun c:ppurge ( )(command “purge” “all” “*” “N”)(princ)

))

Blind the user!Blind the user!(he doesn’t really want to know

h t’ i )what’s going on. ..)

(SETVAR “CMDECHO” 0)but don’t forget to turn it back on!but don t forget to turn it back on!

(SETVAR “CMDECHO” 1)

PPurge.LSPg

(Defun c:ppurge ( )(Defun c:ppurge ( )(setvar “cmdecho” 0)(command “purge” “all” “*” “N”)(command purge all * N )(setvar “cmdecho” 1)(princ)

))

Talk to your user with PROMPTTalk to your user with PROMPT

(defun c:clean ( )(defun c:clean ( )(setvar “cmdecho” 0)(prompt “this command will pick up all of your(prompt this command will pick up all of your objects and clean the drawing file…please wait”)(command “erase” “all” “”)(command erase all )(prompt “\nthere..that’s better”)( t “ d h ” 1)(setvar “cmdecho” 1)(princ)

)

SSGET-Getting a selection setSSGET Getting a selection set(a bit tougher…hang on!)

Used to grab a group of objects.

(setq ss1 (ssget))Select objects:

(ssget “x”)grabs all the objects in the drawing

Using SSGET

(defun c:cm ( )(setq ss1 (ssget))(setq ss1 (ssget))(command “copy” ss1 “” “m”)

)

Let’s create a command that does aLet s create a command that does a full circle, rotated objects Polar Array

(defun c:polar ()

Just for fun!ALERTALERT

ALERT sends an ALERT box to the screenALERT sends an ALERT box to the screen with the indicated text

Example: (ALERT “Formatting the hard drive”)(ALERT Formatting the hard drive )

ACAD LSP or ACADDOC LSPACAD.LSP or ACADDOC.LSPAutomatic Visual Lisp Loading

Put frequently used Visual Lisp routines• Put frequently used Visual Lisp routines.• Undefine those AutoCAD commands you y

want to automatically replace with Visual Lisp routinesLisp routines.

• Place partial menu loading instructions

ACAD.LSP

(defun c:ZA ( )(command “Zoom” “All”)(princ))

(defun c:DT ( )(setvar “clayer” “TEXT”)( y )(command “Dtext”)(princ))(princ))

(defun c:bolt ( )(command “insert” “bolt” pause pause pause)(command insert bolt pause pause pause)(princ))

Automatic loading LISP filesAutomatic loading LISP files

ACAD.LSP 2ACADDOC LSP 4ACADDOC.LSP 4ACAD.MNL 5-------------ACAD200X LSP 1ACAD200X.LSP 1ACAD200XDOC.LSP 3

Undefine and Redefine

Permits undefining and redefining the internal AutoCAD commandsinternal AutoCAD commands

Note: AutoCAD commands can always be executed with a leading periodexecuted with a leading period.

S::STARTUPi l ti f ACAD LSPa special section of ACAD.LSP

(defun C:LINE ( )(defun C:LINE ( )(prompt “Shouldn’t you be using Polylines?”)(command “PLINE”))(command PLINE ))

(defun S::STARTUP ( )(command “undefine” “line”)

))

Note: s::startup is the last file to be loaded beforeNote: s::startup is the last file to be loaded before control is handed over to the user.

Ways to torture your coworkers:

ACAD.LSP(defun c:qsave ( )(defun c:qsave ( )

(command “undo” “b” “y”)(command “ qsave” “ qsave”)(command .qsave .qsave )

(defun s::startup ()(command “undefine” “save”)(command undefine save )(command “undefine” “qsave”)(command “undefine” “saveas”)(command undefine saveas )

)

one more means of torture:

(defun c:zoom ( )(command “erase” “L” ““)(command “.zoom”)(princ)

)(defun c:redo ( )

(prompt “You goofed - deal with it!”)(p p g ))(defun c:undo ( )(d u u do ( )

(alert “Get it right the first time!”)

(d f ()(defun c:regen ()(setvar “cmdecho” 0)(command “donut” 0 300000000000 “10,10”)(command “regen”)( g )(command “cmdecho” 1)

))(defun s::startup ( )

(command “undefine” “zoom”)(command undefine zoom )(command “undefine” “undo”)( d “ d fi ” “ d ”)(command “undefine” “redo”)(command “undefine” “regen”)

)

Other evil things to put in s::startup!s::startup!

S::STARTUP(setvar “angbase” “180”)(setvar angbase 180 )OR(setvar “snapang” 0.000001)OROR(command “vpoint” “0,0,-1”)(command “ucsicon” “off”)

What’s wrong with this picture?g p

(1 + 1)(1 + 1)(* 5 .25)(/ 9 2)(/ 9 2)(setq x (+ 1 2)(d f d d(defun d:dimwit (command “text” .5 90 pause)(alert “hit cancel to exit dialog box”)(defun s:startup ( )( p ( )

Review

• LISP stands for. . .• List

• undefine• Acad lsp• List

• Function• Command

• Acad.lsp• s::startup• stringCo a d

• pause• “”

• string

• DEFUN• (princ)

(d)• (d)

Lynn Allenl nn allen@a todesk comlynn.allen@autodesk.com

Lynn’s Blogwww.autodesk.com/blog