py/mpprint.h: Move HOWTO upper.

Add gaps between MP_DEBUG_PRINT_XXX levels.
Move `How to use:` upper before #define MP_DEBUG_PRINT().
Print level names instead of the numbers.

Signed-off-by: Ihor Nehrutsa <IhorNehrutsa@gmail.com>

py/mpprint.h

@@ -82,45 +82,33 @@ int mp_vprintf(const mp_print_t *print, const char *fmt, va_list args);
 // Debug messages during code developing with MP_DEBUG_PRINT(level, ...) & MP_DEBUG_PRINT_LEVEL.
 // An approximate hierarchy of debug levels MP_DEBUG_PRINT_LEVEL is:
 #define MP_DEBUG_PRINT_SUPPRESS 0 // SUPPRESS all messages. Use it in the release version.
-#define MP_DEBUG_PRINT_CRITICAL 1 // For the most CRITICAL errors, often requiring a system reset. Use a message with this level, if possible, raising an exception.
-#define MP_DEBUG_PRINT_ERROR 2 // ERROR requiring program restart, use message with this level before raising an exception.
-#define MP_DEBUG_PRINT_WARNING 3 // WARNING, something went wrong, but you can fix it with additional operations in code right now or may ignore it.
-#define MP_DEBUG_PRINT_INFO 4 // INFO, it is interesting and useful for understanding a bug.
-#define MP_DEBUG_PRINT_DEBUG 5 // DEBUG, more detailed information, dig deeper.
-#define MP_DEBUG_PRINT_TRACE 6 // TRACE, show a flow of the algorithm, like enter/exit a function.
+#define MP_DEBUG_PRINT_CRITICAL 10 // For the most CRITICAL errors, often requiring a system reset. Use a message with this level, if possible, raising an exception.
+#define MP_DEBUG_PRINT_ERROR 20 // ERROR requiring program restart, use message with this level before raising an exception.
+#define MP_DEBUG_PRINT_WARNING 30 // WARNING, something went wrong, but you can fix it with additional operations in code right now or may ignore it.
+#define MP_DEBUG_PRINT_INFO 40 // INFO, it is interesting and useful for understanding a bug.
+#define MP_DEBUG_PRINT_DEBUG 50 // DEBUG, more detailed information, dig deeper.
+#define MP_DEBUG_PRINT_TRACE 60 // TRACE, show a flow of the algorithm, like enter/exit a function.
 // In reality, you may use your own classification of debug levels.
 
 #endif // MICROPY_INCLUDED_PY_MPPRINT_H
 
 // This code is placed after `#endif // MICROPY_INCLUDED_PY_MPPRINT_H` to allow the developer
 // to use several local `MP_DEBUG_PRINT_LEVEL` definitions in separate _.c files.
 // This is not a typo or a bug.
-#if defined(MP_DEBUG_PRINT_LEVEL) && (MP_DEBUG_PRINT_LEVEL > 0)
-
-#if defined(MP_DEBUG_PRINT)
-#undef MP_DEBUG_PRINT
-#endif
 
-#define MP_DEBUG_PRINT(level, ...) \
-    do { \
-        if ((0 < level) && (level <= MP_DEBUG_PRINT_LEVEL)) { \
-            mp_printf(MP_PYTHON_PRINTER, " MP_DEBUG_PRINT_LEVEL=%d : ", level); \
-            mp_printf(MP_PYTHON_PRINTER, __VA_ARGS__); \
-            mp_printf(MP_PYTHON_PRINTER, "\t : FUNC=%s LINE=%d FILE=%s\n", __FUNCTION__, __LINE__, __FILE__); \
-        } \
-    } while (0);
-
-#else
-
-#define MP_DEBUG_PRINT(level, ...)
-
-#endif
 /*
+// Debugging macro for developers.
+
 // How to use:
-// Set MP_DEBUG_PRINT_LEVEL in developed *.C or *.CPP file, for example
-#define MP_DEBUG_PRINT_LEVEL 1000 // show all messages
+// Important! Set MP_DEBUG_PRINT_LEVEL in *.c or *.cpp development file BEFORE any "MicroPython's *.h" includes.
+// For example:
+#define MP_DEBUG_PRINT_LEVEL MP_DEBUG_PRINT_TRACE // show all messages
 // Include mpprint.h after defining the MP_DEBUG_PRINT_LEVEL
 #include "py/mpprint.h"
+...
+#include "py/obj.h"
+#include "py/runtime.h"
+...
 
 // Add MP_DEBUG_PRINT() macro in code, like
 void foo(int arg) {
@@ -139,10 +127,30 @@ void foo(int arg) {
     MP_DEBUG_PRINT(MP_DEBUG_PRINT_TRACE, "Exit foo()")
 }
 
-// It is not a dogma. You may start debugging from level 3.
-#define MP_DEBUG_PRINT_LEVEL 3
-// Then add MP_DEBUG_PRINT(3, ...) and when gets too many messages then change some messages to the next level MP_DEBUG_PRINT(4, ...), or MP_DEBUG_PRINT(2, ...) etc.
-// Then you may change MP_DEBUG_PRINT_LEVEL to 2(reduce printing), and finally to 0(suppress printing).
+// It is not a dogma. You may start debugging from level 30.
+#define MP_DEBUG_PRINT_LEVEL 30
+// Then add MP_DEBUG_PRINT(30, ...) and when gets too many messages then change some messages to the next level MP_DEBUG_PRINT(40, ...), or MP_DEBUG_PRINT(20, ...) etc.
+// Then you may change MP_DEBUG_PRINT_LEVEL to 20(reduce printing), and finally to 0(suppress printing).
 
 // Usually, you will debug one or two source files. Debug printing from other files is suppressed if MP_DEBUG_PRINT_LEVEL is 0 or undefined.
 */
+#if defined(MP_DEBUG_PRINT_LEVEL) && (MP_DEBUG_PRINT_LEVEL > 0)
+
+#if defined(MP_DEBUG_PRINT)
+#undef MP_DEBUG_PRINT
+#endif
+
+#define MP_DEBUG_PRINT(level, ...) \
+    do { \
+        if ((0 < level) && (level <= MP_DEBUG_PRINT_LEVEL)) { \
+            mp_printf(MP_PYTHON_PRINTER, " %s: ", #level); \
+            mp_printf(MP_PYTHON_PRINTER, __VA_ARGS__); \
+            mp_printf(MP_PYTHON_PRINTER, "\t : FUNC=%s LINE=%d FILE=%s\n", __FUNCTION__, __LINE__, __FILE__); \
+        } \
+    } while (0);
+
+#else
+
+#define MP_DEBUG_PRINT(level, ...)
+
+#endif