diff --git a/hawk/lib/gem-skad.c b/hawk/lib/gem-skad.c
index 41db34d1..5245ec50 100644
--- a/hawk/lib/gem-skad.c
+++ b/hawk/lib/gem-skad.c
@@ -103,13 +103,7 @@ static int str_to_ipv6 (const hawk_ooch_t* src, hawk_oow_t len, struct in6_addr*
 
 		ch = *src++;
 
-		if (ch >= '0' && ch <= '9')
-			v1 = ch - '0';
-		else if (ch >= 'A' && ch <= 'F')
-			v1 = ch - 'A' + 10;
-		else if (ch >= 'a' && ch <= 'f')
-			v1 = ch - 'a' + 10;
-		else v1 = -1;
+		v1 = HAWK_XDIGIT_TO_NUM(ch);
 		if (v1 >= 0)
 		{
 			val <<= 4;
diff --git a/hawk/lib/hawk-chr.h b/hawk/lib/hawk-chr.h
index df17e56c..545e2844 100644
--- a/hawk/lib/hawk-chr.h
+++ b/hawk/lib/hawk-chr.h
@@ -84,6 +84,13 @@ typedef enum hawk_ooch_prop_t hawk_ooch_prop_t;
 typedef enum hawk_ooch_prop_t hawk_uch_prop_t;
 typedef enum hawk_ooch_prop_t hawk_bch_prop_t;
 
+#define HAWK_DIGIT_TO_NUM(c) (((c) >= '0' && (c) <= '9')? ((c) - '0'): -1)
+
+#define HAWK_XDIGIT_TO_NUM(c) \
+	(((c) >= '0' && (c) <= '9')? ((c) - '0'): \
+	 ((c) >= 'A' && (c) <= 'F')? ((c) - 'A' + 10): \
+	 ((c) >= 'a' && (c) <= 'f')? ((c) - 'a' + 10): -1)
+
 #if defined(__cplusplus)
 extern "C" {
 #endif
diff --git a/hawk/lib/parse.c b/hawk/lib/parse.c
index 87c9270f..07970b5b 100644
--- a/hawk/lib/parse.c
+++ b/hawk/lib/parse.c
@@ -5983,12 +5983,12 @@ static int get_number (hawk_t* hawk, hawk_tok_t* tok)
 
 	c = hawk->sio.last.c;
 
-	if (c == HAWK_T('0'))
+	if (c == '0')
 	{
 		ADD_TOKEN_CHAR (hawk, tok, c);
 		GET_CHAR_TO (hawk, c);
 
-		if (c == HAWK_T('x') || c == HAWK_T('X'))
+		if (c == 'x' || c == 'X')
 		{
 			/* hexadecimal number */
 			do 
@@ -6000,7 +6000,7 @@ static int get_number (hawk_t* hawk, hawk_tok_t* tok)
 
 			return 0;
 		}
-		else if (c == HAWK_T('b') || c == HAWK_T('B'))
+		else if (c == 'b' || c == 'B')
 		{
 			/* binary number */
 			do
@@ -6008,20 +6008,20 @@ static int get_number (hawk_t* hawk, hawk_tok_t* tok)
 				ADD_TOKEN_CHAR (hawk, tok, c);
 				GET_CHAR_TO (hawk, c);
 			} 
-			while (c == HAWK_T('0') || c == HAWK_T('1'));
+			while (c == '0' || c == '1');
 
 			return 0;
 		}
 		else if (c != '.')
 		{
 			/* octal number */
-			while (c >= HAWK_T('0') && c <= HAWK_T('7'))
+			while (c >= '0' && c <= '7')
 			{
 				ADD_TOKEN_CHAR (hawk, tok, c);
 				GET_CHAR_TO (hawk, c);
 			}
 
-			if (c == HAWK_T('8') || c == HAWK_T('9'))
+			if (c == '8' || c == '9')
 			{
 				hawk_seterrfmt (hawk, &hawk->tok.loc, HAWK_ELXCHR, HAWK_T("invalid digit '%jc'"), (hawk_ooch_t)c);
 				return -1;
@@ -6037,7 +6037,7 @@ static int get_number (hawk_t* hawk, hawk_tok_t* tok)
 		GET_CHAR_TO (hawk, c);
 	} 
 
-	if (c == HAWK_T('.'))
+	if (c == '.')
 	{
 		/* floating-point number */
 		SET_TOKEN_TYPE (hawk, tok, TOK_FLT);
@@ -6052,14 +6052,14 @@ static int get_number (hawk_t* hawk, hawk_tok_t* tok)
 		}
 	}
 
-	if (c == HAWK_T('E') || c == HAWK_T('e'))
+	if (c == 'E' || c == 'e')
 	{
 		SET_TOKEN_TYPE (hawk, tok, TOK_FLT);
 
 		ADD_TOKEN_CHAR (hawk, tok, c);
 		GET_CHAR_TO (hawk, c);
 
-		if (c == HAWK_T('+') || c == HAWK_T('-'))
+		if (c == '+' || c == '-')
 		{
 			ADD_TOKEN_CHAR (hawk, tok, c);
 			GET_CHAR_TO (hawk, c);
diff --git a/hawk/lib/utl-str.c b/hawk/lib/utl-str.c
index e4288bfb..59189049 100644
--- a/hawk/lib/utl-str.c
+++ b/hawk/lib/utl-str.c
@@ -2628,17 +2628,9 @@ hawk_int_t hawk_uchars_to_int (const hawk_uch_t* str, hawk_oow_t len, int option
 	pp = p;
 	while (p < end)
 	{
-		if (*p >= '0' && *p <= '9') {
-			digit = *p - '0'; }
-		else if (*p >= 'A' && *p <= 'Z')
-			digit = *p - 'A' + 10;
-		else if (*p >= 'a' && *p <= 'z')
-			digit = *p - 'a' + 10;
-		else break;
-
-		if (digit >= base) break;
+		digit = HAWK_XDIGIT_TO_NUM(*p);
+		if (digit <= - 1 || digit >= base) break;
 		n = n * base + digit;
-
 		p++;
 	}
 
@@ -2722,17 +2714,9 @@ hawk_int_t hawk_bchars_to_int (const hawk_bch_t* str, hawk_oow_t len, int option
 	pp = p;
 	while (p < end)
 	{
-		if (*p >= '0' && *p <= '9')
-			digit = *p - '0';
-		else if (*p >= 'A' && *p <= 'Z')
-			digit = *p - 'A' + 10;
-		else if (*p >= 'a' && *p <= 'z')
-			digit = *p - 'a' + 10;
-		else break;
-
-		if (digit >= base) break;
+		digit = HAWK_XDIGIT_TO_NUM(*p);
+		if (digit <= - 1 || digit >= base) break;
 		n = n * base + digit;
-
 		p++;
 	}
 
@@ -3314,11 +3298,6 @@ int hawk_bchars_to_num (int option, const hawk_bch_t* ptr, hawk_oow_t len, hawk_
 
 /* ------------------------------------------------------------------------ */
 
-#define XDIGIT_TO_NUM(c) \
-	(((c) >= '0' && (c) <= '9')? ((c) - '0'): \
-	 ((c) >= 'A' && (c) <= 'F')? ((c) - 'A' + 10): \
-	 ((c) >= 'a' && (c) <= 'f')? ((c) - 'a' + 10): -1)
-
 int hawk_uchars_to_bin (const hawk_uch_t* hex, hawk_oow_t hexlen, hawk_uint8_t* buf, hawk_oow_t buflen)
 {
 	const hawk_uch_t* end = hex + hexlen;
@@ -3328,14 +3307,14 @@ int hawk_uchars_to_bin (const hawk_uch_t* hex, hawk_oow_t hexlen, hawk_uint8_t*
 	{
 		int v;
 
-		v = XDIGIT_TO_NUM(*hex);
+		v = HAWK_XDIGIT_TO_NUM(*hex);
 		if (v <= -1) return -1;
 		buf[bi] = buf[bi] * 16 + v;
 
 		hex++;
 		if (hex >= end) return -1;
 
-		v = XDIGIT_TO_NUM(*hex);
+		v = HAWK_XDIGIT_TO_NUM(*hex);
 		if (v <= -1) return -1;
 		buf[bi] = buf[bi] * 16 + v;
 
@@ -3355,14 +3334,14 @@ int hawk_bchars_to_bin (const hawk_bch_t* hex, hawk_oow_t hexlen, hawk_uint8_t*
 	{
 		int v;
 
-		v = XDIGIT_TO_NUM(*hex);
+		v = HAWK_XDIGIT_TO_NUM(*hex);
 		if (v <= -1) return -1;
 		buf[bi] = buf[bi] * 16 + v;
 
 		hex++;
 		if (hex >= end) return -1;
 
-		v = XDIGIT_TO_NUM(*hex);
+		v = HAWK_XDIGIT_TO_NUM(*hex);
 		if (v <= -1) return -1;
 		buf[bi] = buf[bi] * 16 + v;