Programming Designs Forums

Heard about it once , but never seen it though
I'll research it

I hate it when I dunno sumthin'

Here is some lisp code I got from
http://lib.store.yahoo.net/lib/paulgraham/acl2.lisp


(defun compress (x)
  (if (consp x)
      (compr (car x) 1 (cdr x))
      x))

(defun compr (elt n lst)
  (if (null lst)
      (list (n-elts elt n))
      (let ((next (car lst)))
        (if (eql next elt)
            (compr elt (+ n 1) (cdr lst))
            (cons (n-elts elt n)
                  (compr next 1 (cdr lst)))))))

(defun n-elts (elt n)
  (if (> n 1)
      (list n elt)
      elt))

I want to learn it, but it looks like it's a Mac language... I'm not sure.

You can download free LISP compilers/IDEs at:
http://www.lisp.org/table/systems.htm

I'm looking up LISP's capabilities...

Looking good , but not for me though , i don't even like java :mrgreen:
Visual Basic Rocks.

No Comment

:roll:

The only place I've seen this is with plugin coding.  The syntax is very strange.

sure , it's complicated but, if its use is greater than its difficulty, you should learn it.  :chinese:

Lisp is cool in a few ways, but the one that strikes most people is that everything is a list. Hence, it is a pretty good list processor. When the first element of a list is not escaped (quoted - described below), that element is read by the interpreter as a command. It doesn't become clear until you use it a while, but this means that you can treat Lisp code as a data structure. Now that's powerful.

Depending on the command, the interpreter will look for an embedded list, which may start with another command, or parameters, or arguments. It is very elegant this way, but not immediately intuitive. Once you learn a little syntax, you can do a great deal with it.

Some syntax notes:
A list is zero or more elements surrounded by parens.
Lists can contain sublists.
Lists are processed from the innermost list outward. If two or more lists are at the same level of embeddedness, they are processed right-to-left (I think - it hasn't ever mattered to me).
A command as the first element of a list will be processed as, yup, a command.

A few samples (colon represents the user prompt and the following line shows the interpreter's output:
: (+ 3 4)
7

: (+ 12 (* 2 6))
24

: (+ (* 3 4) (* 2 6))
24

: (* (+ 2 3 4) (* 2 3))
54

More syntax and examples:
A single quote before a list "quotes" the whole list.
:'(+ a b c)
(+ a b c)

Common predications end with 'p.'
: (integerp 2)
T

Top-level commands all start with colon, comments start with semi-colon:
: :res   ; resets the debugger
: :ld <file_name>    ; loads <file_name>
: :exit  ; exits the "listener"

I'm just getting started in Lisp (Common Lisp), and am learning to love it. Some really great books are written for Lisp and Scheme like "The Elements of AI: an Introduction Using Lisp" http://www.amazon.com/Elements-Artifici … amp;sr=8-1 and SICP http://mitpress.mit.edu/sicp/.

And, that is all I have time for tonight. There are already plenty of really good tutorials on Lisp. I suggest you give it a week or two and see if you like it.

D