Setting a variable with LIST

[bpdav1]

Hi, I am learning Autolisp and am trying to create a simple program but have run into the following problem. I am trying to draw a line of user defined length and therefore want to create a variable that allows the user to input the length of the line.

 

When I try to assign "p1" with a value, with no quote mark it says "error: bad function:" If I put the quote mark in (as shown below) it makes the first entry literally the string "Length", not the value of the variable Length. I want the first entry of p1 to be assigned with the value the user inputs, so if you input "1000" into Length, p1 will display as "1000,0", so I can then use it as a coordinate for the Line command.

 

(defun C:Line (/ Length p1)
(setq Length (getint "Enter Length of Line: "))
(setq p1 (list '(Length 0)))
(princ p1)
(princ)
)

[MSasu]

This is from the use of quote instead of LIST function for a list that should be evaluated since contains a variable.

(defun C:[color=red]LineX[/color] ( / [color=red]theLength[/color] p1)
(setq [color=red]theLength[/color] (getint "Enter Length of Line: "))
(setq p1 (list ([color=red]list[/color] [color=red]theLength[/color] 0)))
(princ p1)
(princ)
)

Also, please pay special attention when assign names to your variables/functions and avoid using reserved names!

In your code you will redefine the built-in LINE command and also replace the LENGTH function. This may generate serious errors. I have renamed those in above example.

 

However to get a string as you said, you need to use the STRCAT function; take care that accepts only strings as arguments, so user's input should be converted.

(defun C:LineX ( / theLength p1 )
(setq theLength (getint "Enter Length of Line: "))
(setq p1 [color=red](strcat (itoa theLength) ",0")[/color])
(princ p1)
(princ)
)

[MSasu]

I have rewritten your routine as example:

(defun C:LineX( / theLength pointStart pointEnd )
(if (and (setq pointStart (getpoint "\nStarting point: "))
         (setq theLength  (getint "\nEnter Length of Line: ")))
 (progn
  (setq pointEnd (polar pointStart 0.0 theLength))
  (command "_.LINE" "_non" pointStart "_non" pointEnd "")
 )
)
(princ)
)

Should check the POLAR function in help if you want to adjust the angle of the line.