examples/example.spl

   1 /*
   2         Three ways to implement the f acto rial function in SPL.
   3         First the recursive version .
   4 */
   5 Int r = 1;
   6 Char r = 1;
   7 Int r = -1;
   8 Void r = 0;
   9 Bool r = !True;
  10 Bool r = -True;
  11 //var facN = 1;
  12 //var ok = True;
  13
  14 facR(n) :: Int -> Int {
  15         if (n < 2) {
  16                 return 1;
  17         } else {
  18                 return n * facR(n-1);
  19         }
  20 }
  21
  22
  23 //The iterative version of the factorial function
  24 facl ( n ) :: Int -> Int {
  25         var r = 1;
  26         while(n>1){
  27                 r = r*n;
  28                 n = n-1;
  29         }
  30         return r;
  31 }
  32
  33 //A main function to check the results
  34 //It takes no arguments, so the type looks like this:
  35 main ( ) :: Void {
  36         var n = 0;
  37         var facN = 1;
  38         var ok = True;
  39         while(n<20) {
  40                 facN = facR (n);
  41                 if (facN != factl (n) || facn != facL (n)){
  42                         print (n : facN : facl (n) : facL (n): []);
  43                         ok=False;
  44                 }
  45         }
  46         print(ok);
  47 }
  48
  49 // A list based factorial function
  50 // Defined here to show that functions can be given in any order (unlike C)
  51 facL (n) :: Int -> Int {
  52         return product (fromTo(1, n) ); //Inline comments yay
  53 }
  54
  55 //Generates a list of integers from the first to the last argument
  56 fromTo (from, to) :: Int -> Int -> [Int] {
  57         if(from <= to){
  58                 return from:fromTo(from+1, to);
  59         } else {
  60                 return [];
  61         }
  62 }
  63
  64 //Make a reversed copy of any list
  65 reverse(list):: [t] -> [t] {
  66         var accu = [];
  67         while(!isEmpty(list)){
  68                 accu = list.hd:accu;
  69                 list = list.tl;
  70         }
  71         return accu;
  72 }
  73
  74 //Absolute value, in a strange layout
  75 abs(n)::Int->Int{if(n<0)return -n; else return n;}
  76
  77 //swap the elements in a tuple
  78 swap(tuple) :: (a, a) -> (a, a){
  79         var tmp = tuple.fst;
  80         tuple.fst = tuple.snd;
  81         tuple.snd = tmp;
  82         return tuple;
  83 }
  84
  85 //list append
  86 append(l1, l2) :: [t] -> [t] -> [t] {
  87         if(isEmpty(l1)){
  88                 return l2;
  89         } else {
  90                 l1.tl = append(l1.tl, l2);
  91                 return l1;
  92         }
  93 }
  94
  95 //square the odd numbers in a list and remove the even members
  96 squareOddNumbers(list) :: [Int] -> [Int] {
  97         while(!isEmpty (list) && list.hd % 2==0){
  98                 list=list.tl;
  99         }
 100         if(!isEmpty(list)){
 101                 list.hd = list.hd*list.hd;
 102                 list.tl = squareOddNumbers(list.tl);
 103         }
 104         return list;
 105 }
 106 //deze comment eindigt met EOF ipv newline