ppOp Minus x1 x2 = infl 20 (annotate opr "-") (grouped x1) (grouped x2)
ppOp Minus x1 x2 = infl 20 (annotate opr "-") (grouped x1) (grouped x2)
ppOp Minus x1 x2 = infl 20 (annotate opr "-") (grouped x1) (grouped x2)