diff --git a/HISTORY b/HISTORY
index 55f0a9d..e7af3c9 100755
--- a/HISTORY
+++ b/HISTORY
@@ -1,3 +1,7 @@
+Mar. 1 2016
+Added an OS statement
+Refactored platform dependent macros
+
 Feb. 29 2016
 Added multi-line comment support
 Fixed a crash bug with an invalid expression
diff --git a/core/my_basic.c b/core/my_basic.c
index 1612213..93cd77a 100755
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -30,15 +30,15 @@
 #endif /* _MSC_VER */
 
 #include "my_basic.h"
-#ifdef _MSC_VER
+#ifdef MB_CP_VC
 #	include <conio.h>
 #	include <malloc.h>
-#else /* _MSC_VER */
+#else /* MB_CP_VC */
 #	include <stdint.h>
-#endif /* _MSC_VER */
-#ifndef ARDUINO
+#endif /* MB_CP_VC */
+#ifndef MB_CP_ARDUINO
 #	include <memory.h>
-#endif /* ARDUINO */
+#endif /* MB_CP_ARDUINO */
 #include <assert.h>
 #include <ctype.h>
 #include <limits.h>
@@ -51,26 +51,26 @@
 extern "C" {
 #endif /* __cplusplus */
 
-#ifdef _MSC_VER
+#ifdef MB_CP_VC
 #	pragma warning(push)
 #	pragma warning(disable : 4127)
 #	pragma warning(disable : 4305)
 #	pragma warning(disable : 4309)
 #	pragma warning(disable : 4805)
 #	pragma warning(disable : 4996)
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
 
-#ifdef __APPLE__
+#ifdef MB_CP_CLANG
 #	pragma clang diagnostic push
 #	pragma clang diagnostic ignored "-Wunused-function"
 #	pragma clang diagnostic ignored "-Wunused-variable"
-#endif /* __APPLE__ */
+#endif /* MB_CP_CLANG */
 
-#ifdef __BORLANDC__
+#ifdef MB_CP_BORLANDC
 #	pragma warn -8004
 #	pragma warn -8008
 #	pragma warn -8012
-#endif /* __BORLANDC__ */
+#endif /* MB_CP_BORLANDC */
 
 #ifdef MB_COMPACT_MODE
 #	pragma pack(1)
@@ -1684,22 +1684,22 @@ static int _close_coll_lib(mb_interpreter_t* s);
 */
 
 /** Macro */
-#ifdef _MSC_VER
-#	if _MSC_VER < 1300
+#ifdef MB_CP_VC
+#	if MB_CP_VC < 1300
 #		define MB_FUNC 0
-#	else /* _MSC_VER < 1300 */
+#	else /* MB_CP_VC < 1300 */
 #		define MB_FUNC __FUNCTION__
-#	endif /* _MSC_VER < 1300 */
-#elif defined __BORLANDC__
+#	endif /* MB_CP_VC < 1300 */
+#elif defined MB_CP_BORLANDC
 #	define MB_FUNC __FUNC__
-#elif defined __POCC__
+#elif defined MB_CP_PELLESC
 #	define MB_FUNC __func__
-#else /* _MSC_VER */
+#else /* MB_CP_VC */
 #	define MB_FUNC __FUNCTION__
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
 
-#ifdef _MSC_VER
-#	if _MSC_VER < 1300
+#ifdef MB_CP_VC
+#	if MB_CP_VC < 1300
 #		define _do_nothing(__s, __l, __exit, __result) \
 			do { \
 				_ls_node_t* ast = 0; static int i = 0; ++i; \
@@ -1707,8 +1707,8 @@ static int _close_coll_lib(mb_interpreter_t* s);
 				ast = (_ls_node_t*)(*(__l)); \
 				_handle_error_on_obj((__s), SE_RN_WRONG_FUNCTION_REACHED, (__s)->source_file, DON(ast), MB_FUNC_ERR, __exit, __result); \
 			} while(0)
-#	endif /* _MSC_VER < 1300 */
-#endif /* _MSC_VER */
+#	endif /* MB_CP_VC < 1300 */
+#endif /* MB_CP_VC */
 #ifndef _do_nothing
 #	define _do_nothing(__s, __l, __exit, __result) \
 		do { \
@@ -4145,7 +4145,7 @@ static mb_input_func_t _get_inputer(mb_interpreter_t* s) {
 
 static char* _load_file(mb_interpreter_t* s, const char* f, const char* prefix) {
 	/* Read all content of a file into a buffer */
-#ifndef ARDUINO
+#ifndef MB_CP_ARDUINO
 	FILE* fp = 0;
 	char* buf = 0;
 	long curpos = 0;
@@ -4186,9 +4186,9 @@ static char* _load_file(mb_interpreter_t* s, const char* f, const char* prefix)
 	}
 
 	return buf;
-#else /* ARDUINO */
+#else /* MB_CP_ARDUINO */
 	return 0;
-#endif /* ARDUINO */
+#endif /* MB_CP_ARDUINO */
 }
 
 static void _end_of_file(_parsing_context_t* context) {
@@ -15093,11 +15093,11 @@ static int _std_input(mb_interpreter_t* s, void** l) {
 	obj = (_object_t*)ast->data;
 
 	if(!obj || obj->type == _DT_EOS) {
-#ifdef _MSC_VER
+#ifdef MB_CP_VC
 		getch();
-#else /* _MSC_VER */
+#else /* MB_CP_VC */
 		_get_inputer(s)(line, sizeof(line));
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
 
 		goto _exit;
 	}
@@ -15906,19 +15906,19 @@ _exit:
 #	pragma pack()
 #endif /* MB_COMPACT_MODE */
 
-#ifdef __BORLANDC__
+#ifdef MB_CP_BORLANDC
 #	pragma warn .8004
 #	pragma warn .8008
 #	pragma warn .8012
-#endif /* __BORLANDC__ */
+#endif /* MB_CP_BORLANDC */
 
-#ifdef __APPLE__
+#ifdef MB_CP_CLANG
 #	pragma clang diagnostic pop
-#endif /* __APPLE__ */
+#endif /* MB_CP_CLANG */
 
-#ifdef _MSC_VER
+#ifdef MB_CP_VC
 #	pragma warning(pop)
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
 
 #ifdef __cplusplus
 }
diff --git a/core/my_basic.h b/core/my_basic.h
index 68750b4..98e701d 100755
--- a/core/my_basic.h
+++ b/core/my_basic.h
@@ -30,6 +30,60 @@
 extern "C" {
 #endif /* __cplusplus */
 
+#if defined _MSC_VER
+#	define MB_CP_VC _MSC_VER
+#elif defined __clang__
+#	define MB_CP_CLANG
+#elif defined __CYGWIN__
+#	define MB_CP_CYGWIN
+#elif defined __MINGW32__
+#	define MB_CP_MINGW32
+#elif defined __BORLANDC__
+#	define MB_CP_BORLANDC
+#elif defined __POCC__
+#	define MB_CP_PELLESC
+#elif defined __TINYC__
+#	define MB_CP_TCC
+#elif defined __GNUC__ || defined __GNUG__
+#	define MB_CP_GCC
+#elif defined __ICC || defined __INTEL_COMPILER
+#	define MB_CP_ICC
+#elif defined __HP_cc || defined __HP_aCC
+#	define MB_CP_HPC
+#elif defined __IBMC__ || defined __IBMCPP__
+#	define MB_CP_IBMC
+#elif defined __PGI
+#	define MB_CP_PGCC
+#elif defined __SUNPRO_C || defined__SUNPRO_CC
+#	define MB_CP_SOLARISC
+#elif defined ARDUINO
+#	define MB_CP_ARDUINO
+#else
+#	define MB_CP_UNKNOWN
+#endif /* Compiler dependent macro */
+
+#if defined _WIN32 || defined _WIN64
+#	define MB_OS_WIN
+#elif defined __APPLE__
+#	include <TargetConditionals.h>
+#	define MB_OS_APPLE
+#	ifdef TARGET_OS_IPHONE
+#		define MB_OS_IOS
+#	elif defined TARGET_IPHONE_SIMULATOR
+#		define MB_OS_IOS_SIM
+#	elif defined TARGET_OS_MAC
+#		define MB_OS_MAC
+#	endif
+#elif defined __unix__
+#	define MB_OS_UNIX
+#elif defined __linux__
+#	define MB_OS_LINUX
+#elif defined __ANDROID__
+#	define MB_OS_ANDROID
+#else
+#	define MB_OS_UNKNOWN
+#endif /* OS dependent macro */
+
 #ifndef MBAPI
 #	define MBAPI
 #endif /* MBAPI */
@@ -156,17 +210,17 @@ extern "C" {
 #endif /* MB_NULL_STRING */
 
 #ifndef mb_stricmp
-#	ifdef _MSC_VER
+#	ifdef MB_CP_VC
 #		define mb_stricmp _strcmpi
-#	else /* _MSC_VER */
-#		ifdef __BORLANDC__
+#	else /* MB_CP_VC */
+#		ifdef MB_CP_BORLANDC
 #			define mb_stricmp stricmp
-#		elif defined __POCC__
+#		elif defined MB_CP_PELLESC
 #			define mb_stricmp _stricmp
 #		else
 #			define mb_stricmp strcasecmp
 #		endif
-#	endif /* _MSC_VER */
+#	endif /* MB_CP_VC */
 #endif /* mb_stricmp */
 
 #ifndef mb_assert
diff --git a/output/my_basic.exe b/output/my_basic.exe
index f5df4eb..e9175d2 100755
Binary files a/output/my_basic.exe and b/output/my_basic.exe differ
diff --git a/shell/main.c b/shell/main.c
index 90639c1..bd72d71 100755
--- a/shell/main.c
+++ b/shell/main.c
@@ -30,59 +30,59 @@
 #endif /* _MSC_VER */
 
 #include "../core/my_basic.h"
-#ifdef _MSC_VER
+#ifdef MB_CP_VC
 #	include <crtdbg.h>
 #	include <conio.h>
 #	include <Windows.h>
-#elif !defined __BORLANDC__ && !defined __TINYC__
+#elif !defined MB_CP_BORLANDC && !defined MB_CP_TCC
 #	include <unistd.h>
-#endif /* _MSC_VER */
-#ifndef _MSC_VER
+#endif /* MB_CP_VC */
+#ifndef MB_CP_VC
 #	include <stdint.h>
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
+#ifdef MB_CP_CLANG
+#	include <sys/time.h>
+#endif /* MB_CP_CLANG */
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
 #include <time.h>
-#ifdef __APPLE__
-#	include <sys/time.h>
-#endif /* __APPLE__ */
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
 
-#ifdef _MSC_VER
+#ifdef MB_CP_VC
 #	pragma warning(disable : 4127)
 #	pragma warning(disable : 4706)
 #	pragma warning(disable : 4996)
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
 
-#ifdef __BORLANDC__
+#ifdef MB_CP_BORLANDC
 #	pragma warn -8004
 #	pragma warn -8008
 #	pragma warn -8066
-#endif /* __BORLANDC__ */
+#endif /* MB_CP_BORLANDC */
 
-#ifdef __POCC__
+#ifdef MB_CP_PELLESC
 #	define strdup _strdup
 #	define unlink _unlink
-#endif /* __POCC__ */
+#endif /* MB_CP_PELLESC */
 
 /*
 ** {========================================================
 ** Common declarations
 */
 
-#ifdef _MSC_VER
+#ifdef MB_OS_WIN
 #	define _BIN_FILE_NAME "my_basic"
-#elif defined __APPLE__
+#elif defined MB_OS_MAC
 #	define _BIN_FILE_NAME "my_basic_mac"
-#else /* _MSC_VER */
+#else
 #	define _BIN_FILE_NAME "my_basic_bin"
-#endif /* _MSC_VER */
+#endif
 
 /* Define as 1 to use memory pool, 0 to disable */
 #define _USE_MEM_POOL 1
@@ -646,11 +646,11 @@ static bool_t _try_import(struct mb_interpreter_t* s, const char* p) {
 */
 
 static void _clear_screen(void) {
-#ifdef _MSC_VER
+#ifdef MB_OS_WIN
 	system("cls");
-#else /* _MSC_VER */
+#else /* MB_OS_WIN */
 	system("clear");
-#endif /* _MSC_VER */
+#endif /* MB_OS_WIN */
 }
 
 static int _new_program(void) {
@@ -821,13 +821,13 @@ static void _kill_program(const char* path) {
 
 static void _list_directory(const char* path) {
 	char line[_MAX_LINE_LENGTH];
-#ifdef _MSC_VER
+#ifdef MB_OS_WIN
 	if(path && *path) sprintf(line, "dir %s", path);
 	else sprintf(line, "dir");
-#else /* _MSC_VER */
+#else /* MB_OS_WIN */
 	if(path && *path) sprintf(line, "ls %s", path);
 	else sprintf(line, "ls");
-#endif /* _MSC_VER */
+#endif /* MB_OS_WIN */
 	system(line);
 }
 
@@ -1065,8 +1065,24 @@ static bool_t _process_parameters(int argc, char* argv[]) {
 ** Scripting interfaces
 */
 
+#ifdef MB_OS_WIN
+#	define _OS "WIN"
+#elif defined MB_OS_IOS || MB_OS_IOS_SIM
+#	define _OS "IOS"
+#elif defined MB_OS_MAC
+#	define _OS "MAC"
+#elif defined MB_OS_UNIX
+#	define _OS "UNIX"
+#elif defined MB_OS_LINUX
+#	define _OS "LINUX"
+#elif defined MB_OS_ANDROID
+#	define _OS "ANDROID"
+#else
+#	define _OS "UNKNOWN"
+#endif /* MB_OS_WIN */
+
 #define _HAS_TICKS
-#if defined _MSC_VER
+#if defined MB_CP_VC
 static int_t _ticks(void) {
 	LARGE_INTEGER li;
 	double freq = 0.0;
@@ -1079,7 +1095,7 @@ static int_t _ticks(void) {
 
 	return ret;
 }
-#elif defined __APPLE__
+#elif defined MB_CP_CLANG
 static int_t _ticks(void) {
 	struct timespec ts;
 	struct timeval now;
@@ -1092,7 +1108,7 @@ static int_t _ticks(void) {
 
 	return (int_t)(ts.tv_sec * 1000 + ts.tv_nsec / 1000000);
 }
-#elif defined __GNUC__
+#elif defined MB_CP_GCC
 static int_t _ticks(void) {
 	struct timespec ts;
 
@@ -1100,9 +1116,9 @@ static int_t _ticks(void) {
 
 	return (int_t)(ts.tv_sec * 1000 + ts.tv_nsec / 1000000);
 }
-#else /* _MSC_VER */
+#else /* MB_CP_VC */
 #	undef _HAS_TICKS
-#endif /* _MSC_VER */
+#endif /* MB_CP_VC */
 
 #ifdef _HAS_TICKS
 static int ticks(struct mb_interpreter_t* s, void** l) {
@@ -1167,6 +1183,20 @@ static int set_importing_dirs(struct mb_interpreter_t* s, void** l) {
 	return result;
 }
 
+static int os(struct mb_interpreter_t* s, void** l) {
+	int result = MB_FUNC_OK;
+
+	mb_assert(s && l);
+
+	mb_check(mb_attempt_open_bracket(s, l));
+
+	mb_check(mb_attempt_close_bracket(s, l));
+
+	mb_check(mb_push_string(s, l, mb_memdup(_OS, (unsigned)(strlen(_OS) + 1))));
+
+	return result;
+}
+
 static int sys(struct mb_interpreter_t* s, void** l) {
 	int result = MB_FUNC_OK;
 	char* arg = 0;
@@ -1345,6 +1375,7 @@ static void _on_startup(void) {
 #endif /* _HAS_TICKS */
 	mb_reg_fun(bas, now);
 	mb_reg_fun(bas, set_importing_dirs);
+	mb_reg_fun(bas, os);
 	mb_reg_fun(bas, sys);
 	mb_reg_fun(bas, trace);
 	mb_reg_fun(bas, raise);
@@ -1365,11 +1396,11 @@ static void _on_exit(void) {
 	_close_mem_pool();
 #endif /* _USE_MEM_POOL */
 
-#if defined _MSC_VER && !defined _WIN64
+#if defined MB_CP_VC && !defined _WIN64
 	if(!!_CrtDumpMemoryLeaks()) { _asm { int 3 } }
 #elif _USE_MEM_POOL
 	if(alloc_count > 0 || alloc_bytes > 0) { mb_assert(0 && "Memory leak."); }
-#endif /* _MSC_VER && !_WIN64 */
+#endif /* MB_CP_VC && !_WIN64 */
 }
 
 /* ========================================================} */
@@ -1382,9 +1413,9 @@ static void _on_exit(void) {
 int main(int argc, char* argv[]) {
 	int status = 0;
 
-#if defined _MSC_VER && !defined _WIN64
+#if defined MB_CP_VC && !defined _WIN64
 	_CrtSetBreakAlloc(0);
-#endif /* _MSC_VER && !_WIN64 */
+#endif /* MB_CP_VC && !_WIN64 */
 
 	atexit(_on_exit);