// Quick sort
QS(ret) >< [] => ret~[];
QS(ret) >< (int x):xs =>
	Part(x, left, right)~xs,
	QS(cntl)~left, QS(cntr)~right,
	Append(ret, x:cntl)~cntr;

// Note: `Append' is implemented as built-in.

// Apnd(ret, a)~b  -->  ret ~ b@a
//Apnd(ret, a) >< [] => ret~a;
//Apnd(ret, a) >< x:xs => ret~(x:cnt), Apnd(cnt, a)~xs;

Part(int x, a, b) >< [] => a~[], b~[];
Part(int x, a, b) >< (int y):ys
| y<x => b~(y:cnt), Part(x, a, cnt)~ys
| _   => a~(y:cnt), Part(x, cnt, b)~ys;


const LIST_ELEM=800000;

MkRandList(ret) >< (int n)
| n>0 => ret~(rd:cnt), MkRandList(cnt)~(n-1) 
  where rd=rand(10000)
| _ => ret~[];

MkRandList(cnt)~(LIST_ELEM),
QS(ret)~cnt;
ret;