Initial data commit

Task/Sorting-algorithms-Quicksort/Fe/sorting-algorithms-quicksort-1.fe

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+; utility for list joining
+(= join (fn (a b)
+  (if (is a nil) b (is b nil) a (do
+    (let res a)
+    (while (cdr a) (= a (cdr a)))
+    (setcdr a b)
+    res))))
+
+(= quicksort (fn (lst)
+  (if (not (cdr lst)) lst (do
+    (let pivot (car lst))
+    (let less nil)
+    (let equal nil)
+    (let greater nil)
+    ; filter list for less than pivot, equal to pivot and greater than pivot
+    (while lst
+      (let x (car lst))
+      (if (< x pivot) (= less (cons x less))
+          (< pivot x) (= greater (cons x greater))
+          (= equal (cons x equal)))
+      (= lst (cdr lst)))
+    ; sort 'less' and 'greater' partitions ('equal' partition is always sorted)
+    (= less (quicksort less))
+    (= greater (quicksort greater))
+    ; join partitions to one
+    (join less (join equal greater))))))
+
+(print '(4 65 0 2 -31 99 2 0 83 782 1))
+(print (quicksort '(4 65 0 2 -31 99 2 0 83 782 1)))

Task/Sorting-algorithms-Quicksort/Fe/sorting-algorithms-quicksort-2.fe

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+(4 65 0 2 -31 99 2 0 83 782 1)
+(-31 0 0 1 2 2 4 65 83 99 782)