Purpose

This is the Lisp version of our combination application. It's one of the Palm Samples.

 Requirements

 Source code

Below is the .lisp file.

; Combination.lisp
; Palm
; LispMe

(define (factorial n)
  (if (<= n 1) 1 (* n (factorial (- n 1)))))

(define (combination n p)
  (/ (factorial n) (* (factorial (- n p)) (factorial p))))

(define (go)
  (let ((sock 4))
    (display "Combination > Palm > LispMe")
    (display "#0a")
    (display "#0a")
    (display "factorial(7) = ")
    (display (factorial 7))
    (display "#0a")
    (display "factorial(4) = ")
    (display (factorial 4))
    (display "#0a")
    (display "factorial(3) = ")
    (display (factorial 3))
    (display "#0a")
    (display "combination(7, 4) = ")
    (display (combination 7 4))
    (display "#0a")
    #n))

 Comments

LispMe is a mobile tool. If you love both Lisp and Palm devices, then that's the way to go! It runs directly on your mobile device.

Create a memo category named "LispMe" with Palm Desktop. This is where LispMe will look when you open a file.

Copy and Paste the source code above into a new memo in this LispMe category. Run HotSync. The source code will be stored in a ;Combination.lisp memo. Run LispMe and tap Ld to load the memo. To run the app, just enter (go) and tap Eval.

The core functions are : factorial, combination and go.

Note how functional programming can look weird if you're not used to it: + 7 4 (pre-fixed notation) means 7 + 4 (unfixed notation).

Next sample