Added functions to find if a character is a valid hex value and a valid octal value

misc.go

@@ -131,3 +131,11 @@ func expandSlice[T any](slc []T, newSize int) []T {
 	copy(toRet, slc)
 	return toRet
 }
+
+func isHex(c rune) bool {
+	return slices.Contains([]rune("0123456789abcdefABCDEF"), c)
+}
+
+func isOctal(c rune) bool {
+	return slices.Contains([]rune("01234567"), c)
+}