<code C++>
#include "mainwindow.h"
#include "ui_mainwindow.h"

// Fedora : dnf install qt5-qtdeclarative-devel
// .pro file: qt += qml
#include <QJSEngine>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{
   QString source = ui->input->toPlainText();
   QJSEngine e;
   e.globalObject().setProperty("abc", 7);
   e.globalObject().setProperty("btn", e.newQObject(ui->pushButton));
   e.globalObject().setProperty("txt", e.newQObject(ui->output));
   // btn.text = "button"
   QJSValue v = e.evaluate(source);
   ui->output->append (v.toString());
}

</code>