Initial data commit

Task/Sorting-algorithms-Quicksort/CafeOBJ/sorting-algorithms-quicksort.cafeobj

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+mod! SIMPLE-LIST(X :: TRIV){
+[NeList < List ]
+op [] : -> List
+op [_] : Elt -> List
+op (_:_) : Elt List -> NeList  -- consr
+op _++_ : List List -> List {assoc}  -- concatenate
+var E : Elt
+vars L L' : List
+eq [ E ] = E : [] .
+eq [] ++ L = L .
+eq (E : L) ++ L' = E : (L ++ L') .
+}
+
+mod! QUICKSORT{
+pr(SIMPLE-LIST(NAT))
+op qsort_ : List -> List
+op smaller__ : List  Nat -> List
+op larger__ : List Nat -> List
+
+vars x y : Nat
+vars xs ys : List
+
+eq qsort []  = [] .
+eq qsort (x : xs) = (qsort (smaller xs x)) ++ [ x ]  ++ (qsort (larger xs x)) .
+
+eq smaller []  x = [] .
+eq smaller (x : xs) y = if x <= y then  (x : (smaller xs y)) else (smaller xs y) fi .
+eq larger []  x  = [] .
+eq larger (x : xs) y = if x <= y then (larger xs  y) else (x : (larger xs y)) fi   .
+
+}
+open  QUICKSORT .
+red qsort(5 : 4 : 3 : 2 : 1 : 0 : []) .
+red qsort(5 : 5 : 4 : 3 : 5 : 2 : 1 : 1 : 0 : []) .
+eof