CTMCP Section 2.9 Exercise 9 (a)

CTMCP-Section2.9-9a.oz

declare Sum1 Sum2
Sum1 = proc {$ N ?R}
   local T in
      T=N==0
      if T then R=0
      else
	 local S M in
	    S=N-1
	    {Sum1 S M}
	    R=N+M
	 end
      end
   end
end

Sum2 = proc {$ N S ?R}
   local T in
      T=N==0
      if T then R=S
      else
	 local X Y in
	    X=N-1
	    Y=N+S
	    {Sum2 X Y R}
	 end
      end
   end
end

declare R1 R2
{Sum1 4 R1}
{Browse R1}
{Sum2 5 0 R2}
{Browse R2}