resource mutually_recursive()
#   op fact(k : int) returns f : int, fiction(k : int) returns f : int
#
#     This also works
  op fact(int) returns int, fiction(int) returns int
#

   proc fact(k) returns f
      if k < 0 -> f := -1
      [] k = 0 or k = 1 -> f := 1
      [] k > 1 -> f := k * fiction(k-1)
      fi
   end fact

   proc fiction(k) returns f
      if k < 0 -> f := -1
      [] k = 0 or k = 1 -> f := 1
      [] k > 1 -> f := k + fact(k-1)
      fi
   end fiction

   var n: int
   writes("How many? "); read(n)
   fa i := 1 to n ->
      write(i, "fact is", fact(i), "and", i, "fiction is", fiction(i))
   af
end mutually_recursive

/* ............... Example compile and run(s)

% sr -o mutually_recursive mutually_recursive.sr
% ./mutually_recursive
How many? 5
1 fact is 1 and 1 fiction is 1
2 fact is 2 and 2 fiction is 3
3 fact is 9 and 3 fiction is 5
4 fact is 20 and 4 fiction is 13
5 fact is 65 and 5 fiction is 25
                                              */