diff --git a/version2.0/nasal_misc.h b/version2.0/nasal_misc.h
index 632a671..71a7291 100644
--- a/version2.0/nasal_misc.h
+++ b/version2.0/nasal_misc.h
@@ -12,52 +12,85 @@
 	'0xdeadbeef'
 	'0xDEADBEEF'
 	'0o71230'
+	'1e23'
+	'1E-123'
+	'1.34E10'
 */
+inline bool check_hex_string(std::string str)
+{
+	int len=str.length();
+	for(int i=2;i<len;++i)
+		if(!(('0'<=str[i] && str[i]<='9') || ('a'<=str[i] && str[i]<='f') || ('A'<=str[i] && str[i]<='F')))
+			return false;
+	return true;
+}
+inline bool check_oct_string(std::string str)
+{
+	int len=str.length();
+	for(int i=2;i<len;++i)
+		if(str[i]<'0' || str[i]>'7')
+			return false;
+	return true;
+}
+inline bool check_dec_string(std::string str)
+{
+	int len=str.length();
+	int dot_cnt=0;
+	int i=0;
+	for(;i<len;++i)
+	{
+		if(str[i]=='.')
+		{
+			if(i==len-1)
+				return false;
+			++dot_cnt;
+		}
+		else if(str[i]=='e' || str[i]=='E')
+			break;
+		else if(str[i]<'0' || str[i]>'9')
+			return false;
+	}
+	if(str[i]=='e' || str[i]=='E')
+	{
+		++i;
+		if(i==len)
+			return false;
+		if(str[i]=='-')
+		{
+			++i;
+			if(i==len)
+				return false;
+		}
+		for(;i<len;++i)
+			if(str[i]<'0' || str[i]>='9')
+				return false;
+	}
+	if(dot_cnt>1 || str[0]=='.' || (!dot_cnt && str[0]=='0'))
+		return false;
+	return true;
+}
+
 bool check_numerable_string(std::string str)
 {
-	if(str.length()>1 && str[0]=='-')
+	if(!str.length())
+		return false;
+	if(str[0]=='-' && str.length()>1)
 	{
-		// in lexer this statements are useless
-		// because lexer judge a number that begins with 0~9 (or 0x for hex & 0o for oct)
-		std::string temp="";
-		int str_len=str.length();
-		for(int i=1;i<str_len;++i)
-			temp+=str[i];
-		str=temp;
+		std::string tmp="";
+		for(int i=1;i<str.length();++i)
+			tmp.push_back(str[i]);
+		str=tmp;
 	}
+	else if(str[0]=='-' && str.length()==1)
+		return false;
 	if(str.length()==1 && '0'<=str[0] && str[0]<='9')
 		return true;
 	else if(str.length()>2 && str[0]=='0' && str[1]=='x')
-	{
-		int str_len=str.length();
-		for(int i=2;i<str_len;++i)
-			if(!(('0'<=str[i] && str[i]<='9') || ('a'<=str[i] && str[i]<='f') || ('A'<=str[i] && str[i]<='F')))
-				return false;
-		return true;
-	}
+		return check_hex_string(str);
 	else if(str.length()>2 && str[0]=='0' && str[1]=='o')
-	{
-		int str_len=str.length();
-		for(int i=2;i<str_len;++i)
-			if(!('0'<=str[i] && str[i]<='7'))
-				return false;
-		return true;
-	}
-	else
-	{
-		int str_len=str.length();
-		int float_dot_cnt=0;
-		for(int i=0;i<str_len;++i)
-		{
-			if(str[i]=='.')
-				++float_dot_cnt;
-			else if(!('0'<=str[i] && str[i]<='9'))
-				return false;
-		}
-		if((float_dot_cnt>1) || (str[0]=='.') || (!float_dot_cnt && str[0]=='0'))
-			return false;
-		return true;
-	}
+		return check_oct_string(str);
+	else if('0'<=str[0] && str[0]<='9')
+		return check_dec_string(str);
 	return false;
 }
 
@@ -65,75 +98,102 @@ bool check_numerable_string(std::string str)
 	trans_string_to_number:
 	convert string to number
 */
+inline double hex_to_double(std::string str)
+{
+	double ret=0;
+	int len=str.length();
+	double num_pow=1;
+	for(int i=len-1;i>1;--i)
+	{
+		if('0'<=str[i] && str[i]<='9')
+			ret+=num_pow*(str[i]-'0');
+		else if('a'<=str[i] && str[i]<='f')
+			ret+=num_pow*(str[i]-'a'+10);
+		else if('A'<=str[i] && str[i]<='F')
+			ret+=num_pow*(str[i]-'A'+10);
+		num_pow*=16;
+	}
+	return ret;
+}
+inline double oct_to_double(std::string str)
+{
+	double ret=0;
+	int len=str.length();
+	double num_pow=1;
+	for(int i=len-1;i>1;--i)
+	{
+		ret+=num_pow*(str[i]-'0');
+		num_pow*=8;
+	}
+	return ret;
+}
+inline double dec_to_double(std::string str)
+{
+	double ret=0;
+	int len=str.length();
+	int i=0;
+	for(;i<len;++i)
+	{
+		if('0'<=str[i] && str[i]<='9')
+			ret=ret*10+(str[i]-'0');
+		else if(str[i]=='.' || str[i]=='e' || str[i]=='E')
+			break;
+	}
+	if(str[i]=='.')
+	{
+		++i;
+		double num_pow=0.1;
+		for(;i<len;++i)
+		{
+			if('0'<=str[i] && str[i]<='9')
+			{
+				ret+=num_pow*(str[i]-'0');
+				num_pow*=0.1;
+			}
+			else if(str[i]=='e' || str[i]=='E')
+				break;
+		}
+	}
+	if(str[i]=='e' || str[i]=='E')
+	{
+		
+		++i;
+		bool is_negative=str[i]=='-';
+		if(is_negative)
+			++i;
+		double num_pow=0;
+		for(;i<len;++i)
+			num_pow=num_pow*10+(str[i]-'0');
+		num_pow=std::pow(10,is_negative?-num_pow:num_pow);
+		ret*=num_pow;
+	}
+	return ret;
+}
 double trans_string_to_number(std::string str)
 {
 	bool is_negative=false;
-	if(str.length()>1 && str[0]=='-')
+	double ret_num=0;
+	if(!str.length())
+		return 0;
+	if(str[0]=='-' && str.length()>1)
 	{
-		// in parse this statements are useless
-		// because lexer recognizes a number that begins with a '0'~'9' char
-		std::string temp="";
-		int str_len=str.length();
-		for(int i=1;i<str_len;++i)
-			temp+=str[i];
-		str=temp;
 		is_negative=true;
+		std::string tmp="";
+		for(int i=1;i<str.length();++i)
+			tmp.push_back(str[i]);
+		str=tmp;
 	}
-	double trans_str_number=0;
-	if(str.length()==1)
-		trans_str_number=(double)(str[0]-'0');
-	else if(str[0]=='0' && str[1]=='x')
-	{
-		long long int hex_number=0,bit_pow=1;
-		for(int i=str.length()-1;i>1;--i)
-		{
-			if('0'<=str[i] && str[i]<='9')
-				hex_number+=bit_pow*(str[i]-'0');
-			else if('a'<=str[i] && str[i]<='f')
-				hex_number+=bit_pow*(10+str[i]-'a');
-			else
-				hex_number+=bit_pow*(10+str[i]-'A');
-			bit_pow<<=4;
-		}
-		trans_str_number=(double)hex_number;
-	}
-	else if(str[0]=='0' && str[1]=='o')
-	{
-		long long int oct_number=0,bit_pow=1;
-		for(int i=str.length()-1;i>1;--i)
-		{
-			oct_number+=bit_pow*(str[i]-'0');
-			bit_pow<<=3;
-		}
-		trans_str_number=(double)oct_number;
-	}
-	else
-	{
-		int float_dot_place=str.length();
-		int str_len=str.length();
-		double pow;
-		for(int i=0;i<str_len;++i)
-			if(str[i]=='.')
-			{
-				float_dot_place=i;
-				break;
-			}
-		pow=0.1;
-		for(int i=float_dot_place+1;i<str_len;++i)
-		{
-			trans_str_number+=pow*(double(str[i]-'0'));
-			pow/=10;
-		}
-		pow=1;
-		for(int i=float_dot_place-1;i>=0;--i)
-		{
-			trans_str_number+=pow*(double(str[i]-'0'));
-			pow*=10;
-		}
-	}
-	if(is_negative)
-		trans_str_number*=-1;
-	return trans_str_number;
+	else if(str[0]=='-' && str.length()==1)
+		return 0;
+	if(str.length()==1 && '0'<=str[0] && str[0]<='9')
+		ret_num=(double)(str[0]-'0');
+	else if(str.length()>2 && str[0]=='0' && str[1]=='x')
+		ret_num=hex_to_double(str);
+	else if(str.length()>2 && str[0]=='0' && str[1]=='o')
+		ret_num=oct_to_double(str);
+	else if('0'<=str[0] && str[0]<='9')
+		ret_num=dec_to_double(str);
+	return is_negative?-ret_num:ret_num;
 }
 
 /*