Logging custom objects to QDebug

When you are debugging complex objects, it is nice to output their current members' value to qDebug(). In other languages (such as Java), you may have encountered the toString() method or its equivalent, which is very convenient.

Sure, you could add a function void toString() to each object that you want to log, in order to write code with the following syntax:

qDebug() << "Object content:" << myObject.toString() 

There must be a more natural way of doing this in C++. Moreover, Qt already provides this kind of feature:

QDate today = QDate::currentDate();
qDebug() << today;
// Output: QDate("2016-10-03") 

To achieve this, we will rely on a C++ operator overload. This will look very similar to what we did with QDataStream operators in Chapter 10, Need IPC? Get Your Minions to Work.

Consider a struct Person, as follows:

struct Person {
    QString name;
    int age;
}; 

To add the ability to properly output to QDebug, you just have to override the...