polyline while looping

I'm trying to write a short routine that starts the "pline" command then reads a comma delimited file for each point desired on the pline. The file exists, contains 200-x,y coordinates (eg. 0,0)

My code is:

(defun c:drawfoil ()

(setq f (open "c:/NACA 1212 100points.txt" "r")) ;-Opens the file to read

(command "_pline" dataline "")

(command "LINE" strtpt endpt "")

(while (/= dataline "EOF") ;-Loop until the end of file

(setq dataline (read-line f)) ;-Reads a data line

)

(close f) ;-Close the file

)

The command line looks like:

Command: (load "drawfoil")

C:DRAWFOIL

Command: drawfoil

_pline

Specify start point: EOF

Invalid point.

; error: Function cancelled

Specify start point: *Cancel*

It appears the pline command is happening but I'm getting the "EOF" that I've inserted at the end of the file to stop the looping. What happened to the 200 x,y coordinates that I know exist in this text file?

Any help is appreciated.

msm54

Welcome in the forum!

(defun c:test ()
 (setq f (open "c:/test.txt" "r")) ;-Opens the file to read
 (setq dataline (read-line f))
 (command "_pline" dataline)
 (while dataline
   (command dataline)
   (setq dataline (read-line f))
   )
 (command "")
 (close f) ;-Close the file
)

An advice: turn off OSNAP while runing it

fuccaro,

thanks for the help. this works nicely!

What does the while-loop use to end the looping?

msm54

A variable can be NIL or ... something else (not NIL). If there is data in DATALINE, there is not NIL so the loop goes on. When the file ends, the read will return nothing so DATALINE will hold NIL making it stop.

Understood

thanks kindly

Never mention it. It was my pleasure!