Многоуровневое меню для Arduino и не только

typedef byte ( * tCallback)(byte, byte, char * );

//prototypes NEED FOR CALLBACK
byte callback_StartTimer(byte id, byte parent, char * name);
//struct define typical menu item
struct menuItem {
	byte id;
	char * name;
	byte parent; //id parent
	tCallback callback; //callback function
	bool haveChilds;//using for optimizations
};
vector<menuItem> items;//vector of menu items

int freeRam () { //display free ram memory
	extern int __heap_start, * __brkval;
	int v;
	return (int) & v - (__brkval == 0 ? (int) & __heap_start : (int) __brkval);
}

void setup() {
        menuItem root;
	{
		root.id       = 10;
		root.name     = "Set octave";
		root.parent   = CONST_ROOT_ITEM;
		root.callback = & callback_SetOcave;
		items.push_back(root);

		root.id       = 12;
		root.name     = "Setup";
		root.parent   = CONST_ROOT_ITEM;
		root.callback = NULL;
		items.push_back(root);

		{
			root.id       = 24;
			root.name     = "Time";
			root.parent   = 12;
			root.callback = & callback_resetAllKeys;
			items.push_back(root);
		}
	}
        Serial.println("Free ram: " + String(freeRam()));
}

//call callback of menu item
items[i].callback(id, parent, name);

byte callback_StartTimer(byte id, byte parent, char * name) { //return true if need reprint menu
	//Serial.println("Callbacked function callback_StartTimer by " + String(name));
	return false;
}

//print menu recursively. return need for checking empty menu
bool printMenuRecurcive(vector<menuItem> & items, byte parent, byte level) {
	if (level > CONST_MAX_LEVEL) return false;
	bool haveChilds = false;//flag reports if have items
	for (byte i = 0; i < items.size(); i++) {

		if (parent == items[i].parent) {
			haveChilds = true;//yay! his have items
			String indent = "";

			for (int j = 0; j < level; j++) {
				indent += "  ";
			}

			if (items[i].haveChilds) {
				Serial.println(indent + String(items[i].name) + ">");
			} else {
				Serial.println(indent + String(items[i].name));
			}
			printMenuRecurcive(items, items[i].id, level + 1); //print next level

		}//end if parent
	}//end for
	return haveChilds;
}//end func