private static String[] splitToTwoParams(String param) throws Exception{
		String[] splits=param.split(",");
		if(splits.length==2){//ֻ1šַûиϽṹ
			return splits;
		}else if(splits.length>2){//ж  log(x,log(2,3)) , log(4,6)
			int commaIndex=0;	//ָŵ
			int oddBracket=0;	//ż1żһ
			int spiltCommaCount=0;	//ָ.
			for(int i=0;i<param.length();++i){
				if(param.charAt(i)=='('){
					oddBracket++;
				}else if(param.charAt(i)==')'){
					oddBracket--;
				}else if(param.charAt(i)==','){
					if(oddBracket==0){//ǲָ
						commaIndex=i;
						spiltCommaCount++;
					}
				}
			}
			if(spiltCommaCount==1){//ֻ
				splits=new String[2];
				splits[0]=param.substring(0, commaIndex);
				splits[1]=param.substring(commaIndex+1, param.length());
			}else{
				throw new Exception(ERROR_MESSAGE[FUCTION_PARAMS_ERROR]);
			}
		}else{
			throw new Exception(ERROR_MESSAGE[FUCTION_PARAMS_ERROR]);
		}
		return splits;
	}