topic Re: Creating a hatch into a closed polyline with LISP in AutoCAD Forum

Creating a hatch into a closed polyline with LISP

Anonymous — Sun, 18 Aug 2019 14:36:29 GMT

Dear all,

I want to create a hatch inside a closed polyline with Lisp. Unfortunaly it won't work. My Lisp Code:

(defun FKT:ARROW ()

(command "_.pline" '(0 150) '(600 0) '(0 -150) "_c" "")

(setq ENT (entlast))

(command "_hatch" "SOLID" ENT "")

);defun

I use AutoCAD 2017. Thanks for all your help.

Re: Creating a hatch into a closed polyline with LISP

j.palmeL29YX — Sun, 18 Aug 2019 15:32:12 GMT

This works here:

(defun c:arrow	(/ ent)
  (command "_.pline" '(0 150) '(600 0) '(0 -150) "_c" "")
  (setq ENT (entlast))
  (command "_hatch" "SOLID" ENT "")
  (princ)
)

Re: Creating a hatch into a closed polyline with LISP

Kent1Cooper — Mon, 19 Aug 2019 17:19:13 GMT

If you want to use FKT:ARROW as a command you can type in, put a C: before the name:

(defun C:FKT:ARROW ()

If not, you must use it by entering the function name with enclosing parentheses:

(FKT:ARROW)

Re: Creating a hatch into a closed polyline with LISP

Anonymous — Mon, 19 Aug 2019 17:25:38 GMT

Heureka! - Thanks so much, it works :).

Re: Creating a hatch into a closed polyline with LISP

Anonymous — Mon, 19 Aug 2019 17:34:45 GMT

May can you explain me in addition, why does it works this way? What is the meaning of the command (princ) in this case and why do I have to enter the Symbol ENT inside the brackets behind the slash? Thanks for your support!

Re: Creating a hatch into a closed polyline with LISP

Kent1Cooper — Mon, 19 Aug 2019 17:46:36 GMT

@Anonymous wrote:

May can you explain me in addition, why does it works this way? What is the meaning of the command (princ) in this case and why do I have to enter the Symbol ENT inside the brackets behind the slash? Thanks for your support!

Neither of those is what makes it work. It's the c: before the command name that makes it work.

The (princ) is referred to as "quiet exit" so that you don't see nil at the Command line after you run it -- see Help about that and (prin1) and (print). AutoLisp functions/command-definitions return the last thing in them at the end. This command definition ends with a (command) function, which always returns nil, and that will appear at the Command line and confuse some people if it isn't squelched by ending with a function that does nothing and returns nothing.

The (/ ent) is "localizing variables" -- see Help for the (defun) function. It's not essential, but good practice, and depending on your use of variable names, could prevent different routines interfering with each other.