// Insertion sort
isort(ret) >< [] => ret~(*R)[];
isort(ret) >< x:xs => (*R)I(ret, x)~cnt, (*L)isort(cnt)~xs;

I(ret, int x) >< [] => ret~[x];
I(ret, int x) >< (int y):ys
| x<=y => ret~(*L)(x:(*R)(y:ys))
| _    => (*L)I(cnt, x)~ys, ret~(*R)(y:cnt);


// creates a random list
make_RandList(ret) >< (int n)
| n>0 => ret~(rd:cnt), (*L)make_RandList(cnt)~(n-1) 
  where rd=rand(10000)
| _ => ret~[];


// validation checks
valid(ret) >< [] => ret~True;
valid(ret) >< x:xs => (*L)valid_Cons(ret,x)~xs;

valid_Cons(ret, int x) >< [] => ret~True;
valid_Cons(ret, int x) >< (int y):ys
| x<=y => (*L)valid_Cons(ret,y)~ys
| _ => ret~False, Eraser~ys;

// The `Eraser' is a built-in agent defined for any agents as follows:
//Eraser >< Alpha(a1, ..., a5) => Eraser~a1, ..., Eraser~a5;


// Main
const LIST_ELEM=20000;

make_RandList(rndlist)~(LIST_ELEM),
isort(sorted)~rndlist,
valid(ret)~sorted;

ret;