---------------------------------------------------------------------- -- node Alternate -- input: integer stream X -- output: integer stream Y -- Y starts at X and keeps alternating between the curren -- and the initial value of X ---------------------------------------------------------------------- node Alternate( X : int ) returns ( Y : int ); var A : bool; X1 : int; let A = false -> not (pre A); X1 = X -> pre X1; Y = X -> if A then X else X1; tel