fun insert (tree, value) {
  case tree of
    `Empty                      -> return `Node (value, `Empty, `Empty)
  | `Node (x, left, right) ->
       if x > value
          then return `Node (x, insert (left, value), right)
          else return `Node (x, left, insert (right, value))
       fi
  esac  
}

tree := `Empty;

for i := 0, i <= 10, i := i+1 do
 printf ("%s\n", tree.string);
 tree := insert (tree, i)
od;

printf ("%s\n", tree.string)