new g_Test = 1234;
new g_TestString[32];
new g_Array[5];
new g_ArraySum = 0;

new g_Var1, g_Var2, g_Var3[10];

// The value of g_DynVar will update every time g_Var1/2/3 change
dynamic g_DynVar <- (g_Var1, g_Var2, g_Var3) {
	return g_Var1 + g_Var2 + g_Var3[1] + g_Var3[2];
}

main() {
	// Changing these automatically update g_DynVar
	g_Var1 = 1;
	g_Var2 = 10;
	g_Var3[1] = 100;
	g_Var3[2] = 1000;

	printf("g_DynVar = %d", g_DynVar);

	// Now OnTestChange will be executed
	g_Test = 789;

	print(g_TestString); // Test is 789

	// Every time this happens, OnArrayChange will be executed
	for (new i = 0; i < sizeof(g_Array); i++)
		g_Array[i] = (i + 1) * 10;

	// g_ArraySum will be automatically updated in OnArrayChange
	printf("The sum of g_Array is %d", g_ArraySum);

	for (new i = 0; i < sizeof(g_Array); i++)
		g_Array[i] *= 10;

	printf("The sum of g_Array is %d", g_ArraySum);
}

// Executed every time g_Test is changed
observer OnTestChange(previous, current) {
    printf("Test changed from %d to %d", previous, current);

	// Update a string when this value changes
	format(g_TestString, sizeof(g_TestString), "Test is %d", current);
}

// Executed every time g_Array is changed
observer OnArrayChange(prev, curr, idx) {
	printf("g_Array[%d] %d -> %d", idx, prev, curr);

	// Keep track of the array's sum without ever looping through it
	g_ArraySum += curr - prev;
}

public InstallObservers() {
	ObserveVar(g_Test, OnTestChange);
	ObserveArray(g_Array, OnArrayChange);
}

#include <samp-observer/observe>