print true == true;    // out: true
print true == false;   // out: false
print false == true;   // out: false
print false == false;  // out: true

// Not equal to other types.
print true == 1;        // out: false
print false == 0;       // out: false
print true == "true";   // out: false
print false == "false"; // out: false
print false == "";      // out: false

print true != true;    // out: false
print true != false;   // out: true
print false != true;   // out: true
print false != false;  // out: false

// Not equal to other types.
print true != 1;        // out: true
print false != 0;       // out: true
print true != "true";   // out: true
print false != "false"; // out: true
print false != "";      // out: true