add tutorial in 'Qt_EQL/' for accessing C++ apps from Lisp

Qt_EQL/tutorial/main.cpp

@@ -0,0 +1,27 @@
+#include "test.h"
+#include <eql5/eql.h>
+#include <QApplication>
+#include <QLabel>
+
+int main(int argc, char* argv[]) {
+    QApplication app(argc, argv);
+
+    QLabel* main = new QLabel("<h2>Main Window</h2>");
+    main->setAlignment(Qt::AlignCenter);
+    main->resize(600, 400);
+    main->show();
+
+    // we need an instance for 'define-qt-wrappers' and 'new-instance' to work;
+    // we pass the main widget as parent and a unique 'objectName', so we can
+    // find it from Lisp
+
+    Test test(main, "test");
+
+    EQL eql;
+    EQL::eval("(in-package :eql-user)");
+    EQL::eval("(load \"test.lisp\")");   // will start a REPL
+    app.processEvents();                 // needed for 'qlater' in 'test.lisp'
+
+    return 0;                            // no 'app.exec()' because of REPL
+}
+