cant reenter lisp error

[samifox]

Hi

 

im exploring the (polar) function so i made a loop on the background of a radian scheme. the problem is that i want to enter a lisp expression and see what happening on the scheme but i get "cant reenter lisp error"

 

exampel

 

Command: PLR

Enter a factor :

Command : (* pi 3)

Can't reenter LISP.

 

(defun C:PLR ()
 (setq cen '(20.9463 13.5021 0.0))

 (while (setq n (getstring T "\nEnter a factor :"))
  
   (setq n  (atof n))
   (polar cen n 50)
   (command "line" cen (polar cen n 50) "")
   
   (
   )
 )
)

 

see attachment

 

Thanks

Shay

PLR.dwg

[jdiala]

(defun C:PLR (/ cen)
 (setq cen '(20.9463 13.5021 0.0))
 (while (setq n (getangle  "\nEnter angle:"))
 (command "line" cen (polar cen n 50) "")
 )(princ)
)

[samifox]

(defun C:PLR (/ cen)
 (setq cen '(20.9463 13.5021 0.0))
 (while (setq n (getangle  "\nEnter angle:"))
 (command "line" cen (polar cen n 50) "")
 )(princ)
)

 

please read my massage as well

[satishrajdev]

Samifox..... I tried both code.... on your uploaded file, I didnt get error which you have talked about.

 

following code of jdiala's working properly than to yours....

 

(defun C:PLR (/ cen [color=red]n[/color])
 (setq cen '(20.9463 13.5021 0.0))
 (while (setq n (getangle  "\nEnter angle:"))
 (command "line" cen (polar cen n 50) "")
 )(princ)
)

[samifox]

try to type expression like (* pi 2)when you asked to type a factor

[satishrajdev]

Getangle don't accept (* pi 2) so I tried your code which is given below.....

I didnt get any error... see attached image too

When I type (* pi 2) it drawn red line.....

(defun C:PLR (/ cen n)
 (setq cen '(20.9463 13.5021 0.0))
 (while (= (setq n (getstring T "\nEnter a factor :")) nil)
   (command "line" cen (polar cen (atof n) 50) "")
 )
 (princ)
)

[pBe]

_$ (setq n (getstring T "\nEnter a factor :"))
"(* pi 1.5)"
_$ (atof n)
[b]0.0
[/b]

 

Should be at 270....

[pBe]

try to type expression like (* pi 2)when you asked to type a factor

 

Me thinks you should settle with just typing the factor number then construct the expression (* pi n) before passing the argument to polar function.

[MSasu]

Samifox, please pay attention that you cannot input an AutoLISP statement to the prompt of a function from GET* family; excerpt from help:

The user cannot enter another AutoLISP expression as the response to a getangle request.

[samifox]

Me thinks you should settle with just typing the factor number then construct the expression (* pi n) before passing the argument to polar function.[/QUOTe]

 

I DIDNT GET YOU

 

Samifox, please pay attention that you cannot input an AutoLISP statement to the prompt of a function from GET* family; excerpt from help:

 

so can i use expresions from command line or not?

[marko_ribar]

I DIDNT GET YOU

so can i use expresions from command line or not?

 

I think pBe meant this :

(defun C:PLR (/ cen n)
 (setq cen '(20.9463 13.5021 0.0))
 (while (= (setq n (getreal "\nEnter a factor (* pi n) - n: ")) "")
   (command "line" cen (polar cen (* pi n) 50) "")
 )
 (princ)
)

[MSasu]

so can i use expresions from command line or not?

Unfortunately you cannot use AutoLISP expressions at command line when input to the prompt of one of GET* family functions or of commands called from AutoLISP.

 

You can do this for the prompts of built-in commands, as long those where not called from AutoLISP.

[MSasu]

Some examples:

Wrong:

Command: (getreal "\nInput real number: ")

Input real number: (* 2 3.0)

Command: (command "_CIRCLE" pause pause)

CIRCLE

Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: (list 0.0 0.0)

Specify radius of circle or [Diameter]: (* 2 3.0)

 

Correct:

Command: _CIRCLE

Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: (list 0.0 0.0)

Specify radius of circle or [Diameter]: (* 2 3.0)

[pBe]

I think pBe meant this :

....
 (while (= (setq n (getreal "\nEnter a factor (* pi n) - n: ")) "")
   (command "line" cen (polar cen (* pi n) 50) "")
 )
..

 

Thank you Marko, now if samifoxs' intention is to always use (* pi number) then:

 

(defun C:PLR ( / cen n ang)
   (setq cen '(20.9463 13.5021 0.0))
   (while (setq n (getreal "\nEnter a factor (* pi n) - n: "))
     (setq ang (* pi n))
     (while (> ang (* pi 2))
(setq ang (- ang (* pi 2)))
     )
     (command "line" "_non"
       cen "_non"
       (polar cen ang 50)  ""
     )
     (princ (Strcat "(* pi " (rtos n) ") : " (angtos ang 0 2)))
   )
   (princ)
 )

 

but if want to input a different expression every time then you can use something like this

 

(defun C:PLR (/ cen n ang)
   (setq cen '(20.9463 13.5021 0.0))
   (while [color="blue"](/= (setq n (getstring T "\nEnter lisp expression :")) "")[/color]
     [color="blue"](setq _n	n
    ang	(eval (read n))
     )[/color]
     (while (> ang (* pi 2))
(setq ang (- ang (* pi 2)))
     )
     (command "line"
       "_non"
       cen
       "_non"
       (polar cen ang 50)
       ""
     )
    [color="blue"] (princ (Strcat _n " : " (angtos ang 0 2)))[/color]
   )
   (princ)
 )

 

**NOTE: no error trap [its for the OP to add]** (validity of input that is)

 

HTH