printing a text file using lisp

[john_]

can anyone tell me how i would go about printing a simple text file using lisp?

 

im not talking about printing acad text to a file

im specifically looking to add a button to my tool bar that when press ed it will print a specific text file. (.txt)

 

thanks

[The Buzzard]

Hi John,

 

Welcome to the Forum.

 

Have a moderator move your post to

 

AutoLISP, VBA, the CUI & Customisation

 

You can have Lisp questions easily answered there.

[john_]

Hi and thanks

How do I get a moderator to move it?

[The Buzzard]

You can send a private message to any moderator.

They do not want you to duplicate your message.

Or I can contact a moderator for you.

I will contact one for you.

[The Buzzard]

John,

 

I sent a message for you, Please give it a little time.

[john_]

Thank you sir

[Commandobill]

I believe it would be easier if it were a word document and not your basic .txt file. I may be wrong.

[Se7en]

here are two quick methods for reading and displaying text on the command line from a text file.

( (lambda ( f / )
  (defun pars (s f)
    ;; Adopted from: ElpanovEvgeniy
    (if s
      (cons s (pars (read-line f) f)) 
      (close f))  )
  (princ "\n\n")
  (mapcar '(lambda (x) (write-line x)) (pars (read-line f) f))
  (princ)
  )
 (open "C:\\MyFile.txt" "R")
)

 

( (lambda ( f / line )
 (princ "\n\n")
  (while (setq line (read-line f))
    (write-line line))
    (princ) )
 (open "C:\\MyFile.txt" "R")
)

[Lee Mac]

I love that "pars" function - I saw it used at the Swamp a few times - Elpanov is a genius

 

But as for the OP's question - I wasn't certain as to whether he meant print to command-line, file or actually use LISP to print a piece of paper...

[Se7en]

I love that "pars" function - I saw it used at the Swamp a few times - Elpanov is a genius

 

But as for the OP's question - I wasn't certain as to whether he meant print to command-line, file or actually use LISP to print a piece of paper...

 

`pars' is very simple recursion. I cut and paste code and a line like (mapcar '(lambda ( x ) (write-line... is easier then typing the while statement method. The real genius comes in at how the code is ORGANIZED using the two different methods not the code itself.

 

For your homework, tell me what kind or procedure `pars' is. ~

 

 

I wasn't sure so i choose the easy route.

[Lee Mac]

For your homework, tell me what kind or procedure `pars' is. ~

 

I'm inclined to say "recursive", but you already mentioned that so it can't be that easy...

[Se7en]

*sigh* ...Don't make me hit you!

 

It is a recursive procedure using a ____ process.

 

*psssst Hint:* Go get that substitution model write up i gave you.

[David Bethel]

This is a very old routine by Duff Kirkland ( modified to accept all file type extensions ) -David

DDTYPE.DCL

DDTYPE.LSP

[Lee Mac]

*sigh* ...Don't make me hit you!

 

Haha, you can try but you might break your monitor...

 

It is a recursive procedure using an iterative process.

 

*psssst Hint:* Go get that substitution model write up i gave you.

 

I did have to take a quick look at it...

[Se7en]

linear.

 

A tip to determine if it is linear or iterative is to check to see if there is a process yet to be completed after the procedure calls itself.

...
(cons
 ;; construct a list
 s
 (pars (read-line f) f))
 ;; call itself
...

The CONS (a list) has to be evaluated AFTER it calls itself so it is linear (Remember: Lisp is evaluated inside out).

 

Sub model:

(do something)

(do something (do something))

(do something (do something (do something)))

(do something (do something (do something (do something)))

...

(do something (do something))

(do something)

 

What you should be thinking to yourself when you see this is: "If there is a lot of information to be processed, it can be a lot of data on the stack so I have to be careful using it."

 

A recursive procedure using an iterative process is sometimes called a "Tail recursive" procedure. Tail recursive procedures are a bit confusing (I have problems with them myself) but 99% of the recursive AutoLisp procedures you see will be using a linear process. A recursive procedure using an iterative process' sub model would look like this:

 

(do something)

(do something)

(do something)

(do something)

...

(do something)

 

Anyways, that's awesome that you looked. I refer to it all the time myself but i would be happy if you can find some use for it too.

[Lee Mac]

Thanks for the information, I do want to understand these things - but they are sometimes hard to envision step by step.

 

Judging by your explanation, I don't think I've actually seen an iterative process (tail-recursive)... but I have seen quite a few linear ones...

 

For example, I use this quite often (originated from Gile me thinks...)

 

(defun list->3D-point (lst)
 (if lst
   (cons  (list (car lst) (cadr lst) (caddr lst))
          (list->3D-point (cdddr lst))))

I did have one question though: What determines the "stack"? Is it the amount of RAM on the computer? or is it to do with something else? Or am I way off the mark on this one...

[Se7en]

As far as i can tell (ive seen contradicting definitions) is that its the amount of memory (RAM) that the Windows OS allocated to the AutoCAD program upon start up (but i dont know for sure ...I just think of it as a black box of memory). If you find a good def pass it on please.

 

Sure you have. I have an example in that write up.

(map-car-iter
 (lambda (x) (+ x 1))
            '(1 2 3) )

(defun map-car-iter ( proc lst)
  (map-iter '() proc lst) )

(defun map-iter (sofar proc lis) 
  (if (null lis) 
      (reverse sofar) 
      (map-iter (cons (proc (car lis)) 
                      sofar) 
                proc 
                (cdr lis))) )

[Lee Mac]

Sure you have. I have an example in that write up.

(map-car-iter
 (lambda (x) (+ x 1))
            '(1 2 3) )

(defun map-car-iter ( proc lst)
  (map-iter '() proc lst) )

(defun map-iter (sofar proc lis) 
  (if (null lis) 
      (reverse sofar) 
      (map-iter (cons (proc (car lis)) 
                      sofar) 
                proc 
                (cdr lis))) )

 

Blimey, that is a tough one to figure out - I'd better take another look at that write-up...

[Lee Mac]

So, just to clarify, am I right to say this is linear? As the "cons" has not been evaluated before the "recursion"?

[David Bethel]

In DOS days, you had to control stack and heap values in accordance to how much RAM your machine had. Today Windows allocates its as it can. -David

 

http://www.computing.net/answers/programming/waht-is-stack-amp-heap/6345.html