A simple helper for date parsing using the Qt framework.

debug_date_qt.cpp

#include <QCoreApplication>
#include <QDate>
#include <QDebug>
#include <iostream>

enum class debug_date : int32_t
{
    invalid,
    yyyy_mm_dd,
};

template <debug_date Fmt>
void debug_date_qt(const QDate &date) noexcept
{
    if (!date.isValid()) {
        qDebug() << "QDate(\"null\")";
        return;
    }

    switch (Fmt)
    {
    case debug_date::yyyy_mm_dd: {
        qDebug() << date;
        break;
    }
    default:{
        qDebug() << "QDate(\"undefined\")";
        break;
    }
    }
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QDate date(1994, 10, 21);
    date = date.addYears(31);

    // invalid cast
    debug_date_qt<debug_date::invalid>(date);

    // correct cast
    debug_date_qt<debug_date::yyyy_mm_dd>(date);

    // invalid cast
    debug_date_qt<debug_date::yyyy_mm_dd>({});

    return a.exec();
}