public static Operation getInfixOperation(String op, String argL, String argR)
			throws ParseException {
		
		if( "+".equals(op) ){
			return new Sum(argL, argR);
			
		} else if ("-".equals(op)){
			return new Difference(argL, argR);
			
		} else if ("*".equals(op)){
			return new Product(argL, argR);
			
		} else if ("/".equals(op)){
			return new Quotient(argL, argR);
			
		} else if ("^".equals(op)){
			return new Power(argL, argR);
		} else {
			throw new ParseException("THIS SHOULD NEVER HAPPEN, "
					+ "Strange error in getInfixOperation");
		}
	}