hourOrder (f1, t1) (f2, t2)
  | t1 > t2 = GT
  | t1 < t2 = LT
  | t1 == t2 = compare f1 f2
hourOrder (f1, t1) (f2, t2)
  | t1 > t2 = GT
  | t1 < t2 = LT
  | t1 == t2 = compare f1 f2
hourOrder (f1, t1) (f2, t2)
  | t1 > t2 = GT
  | t1 < t2 = LT
  | t1 == t2 = compare f1 f2