Help Importing attributes from Lisp..

Hi All,

I am quite new to an autolisp programming and trying to make a lisp routine which reads xyz from external file and import its z value as a block attribute. So far i've reached is as follows.

(defun c:bthy (/ tpath fd info Bs Bsc BSL eas nor ipt ba tpt x y xs ys) 
 (setq tpath (getfiled "Select XYZ File" "*.*" "" 4))
   (setvar "cmdecho" 0)
   (graphscr)
   (setq fd   (open tpath "r")
  info (read-line fd)
   )
   (if	(/= info nil)
     (progn
(setq Soundings (getfiled "Select Bathymetry Block" "*.*" "dwg" 4))
(setq Bs (Getreal "\nScale factor for Bathymetry Block <1>:"))
(if (= Bs Nil)
  (setq Bsc 1)
  (setq Bsc Bs)
)
     )
     (progn (alert "Bathy file is empty") (exit))
   )
   (setq BSL (rtos Bsc 2 3))
   (while (/= info nil)
     (setq eas	(atof (substr info 1 10))
    nor	(atof (substr info 12 11))
    ipt	(list eas nor)
    ba	(atof (substr info 24 5))
    tpt	(list eas nor ba)
    x	(fix ba)
    y	(fix (* (- ba x) 10))
    xs	(itoa x)
    ys	(itoa y)
     )
     (command "insert" Soundings ipt BSL BSL 0 xs ys)
     (setq info (read-line fd))
   )
   (close fd)
   (COMMAND "zoom" "0.8x")
   (COMMAND "regen")
   (princ)
 )

Here is the dwg for Block.

[ATTACH]35101[/ATTACH]

A file for this code should contain a line as (eg. 500000.000,2150000.000,23.5) any delimiter can be used but X and Y decimal must be 3 and for Z it must be 1.

My request and question here is:

1, i always get a text file which has easting northing and elevation with different decimals on every line, how can i make my code to read the file as i get without changing its decimals from excel.

2, I also get files which includes elevations as positive and even negative (i.e 500000.23, 2154356.355, -25.1 and 500101.2, 2155389.24, 24.1), how can i filter all negatives (-) and insert as (%%.1).

3, Can i give colors for different values as interval in interger given by user..

I hope i am not expecting too big but Please i need help.

Thanks and Regards

Sorry by mistake i have posted the thread two times Please ignore the previous one.

moderator this is twice http://www.cadtutor.net/forum/showthread.php?69781-Help-(List)-to-quot-string-quot