Data commit

Task/Knuth-shuffle/SNOBOL4/knuth-shuffle.sno

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+* Library for random()
+-include 'Random.sno'
+
+*       # String -> array
+        define('s2a(str,n)i') :(s2a_end)
+s2a     s2a = array(n); str = str ' '
+sa1     str break(' ') . s2a<i = i + 1> span(' ') = :s(sa1)f(return)
+s2a_end
+
+*       # Array -> string
+        define('a2s(a)i') :(a2s_end)
+a2s     a2s = a2s a<i = i + 1> ' ' :s(a2s)f(return)
+a2s_end
+
+*       # Knuth shuffle in-place
+        define('shuffle(a)alen,n,k,tmp') :(shuffle_end)
+shuffle n = alen = prototype(a);
+sh1     k = convert(random() * alen,'integer') + 1
+        eq(a<n>,a<k>) :s(sh2)
+        tmp = a<n>; a<n> = a<k>; a<k> = tmp
+sh2     n = gt(n,1) n - 1 :s(sh1)
+        shuffle = a :(return)
+shuffle_end
+
+*       # Test and display
+        a = s2a('1 2 3 4 5 6 7 8 9 10',10)
+        output = a2s(a) '->'
+        shuffle(a)
+        output = a2s(a)
+end