parser grammar ACalcParser;
options { tokenVocab = ACalcLexer; }
prog
  : stmt prog  # Program
  | EOF        # EmptyProg
  ;
stmt : exp STOP ;
exp
  : exp OPA term  # AddSub
  | term          # SingleTerm
  ;
term
  : term OPM factor  # MulDiv
  | factor           # SingleFactor
  ;
factor
  : NUM        # Num
  | LP exp RP  # Parens
  ;