review cpp-lib example

cpp-lib/cpp/cpp.pro

@@ -1,4 +1,4 @@
-QT          += core
+QT          += widgets
 TEMPLATE    = lib
 CONFIG      += plugin release
 DESTDIR     = ../

cpp-lib/cpp/lib.cpp

@@ -1,4 +1,6 @@
 #include "lib.h"
+#include <QApplication>
+#include <QMessageBox>
 #include <QtDebug>
 
 QT_BEGIN_NAMESPACE
@@ -8,18 +10,21 @@ QObject* ini() {
   static QObject* cpp = 0;
   if(!cpp) {
     cpp = new CPP;
+
+    // needed for QMessageBox
+    static int argc = 1;
+    static char* argv[] = {"cpp"};
+    new QApplication(argc, argv);
   }
   return cpp;
 }
 
-// insert here your function implementations
-
 QVariant CPP::hello(const QVariant& arg) {
   QString msg;
   QDebug debug(&msg);
   debug << arg;
 
-  qDebug() << "hello" << arg;
+  QMessageBox::information(nullptr, "hello", msg);
 
   return arg;
 }

cpp-lib/readme.md

@@ -14,26 +14,18 @@ Run
 
 ```
 $ lqml ~/slime/qml-start-swank.lisp
-$ emacs
+
+$ emacs run.lisp
 ```
 
-In Slime do:
-```
-(defvar *cpp* (qload-c++ "cpp"))
+After `M-x slime-connect` and loading `run.lisp`, you can see that, despite
+the argument and return type simply being defined as `QVariant`, you may also
+pass lists, because a `QVariant` can also be of type `QVariantList`, so this
+is a perfect fit for (nested) Lisp lists.
 
-(define-qt-wrappers *cpp*)
-
-(hello *cpp* '(1 "two" (1.25 #(50 -50 75))))
-```
-Now look at the console output where you launched the `lqml` executable.
-
-As you can see, although the argument and return type are simply defined as
-`QVariant`, you may also pass lists, because a `QVariant` can also be of type
-`QVariantList`, so this is a perfect fit for (nested) Lisp lists.
-
-So, we pass a nested Lisp list, and it gets printed on Qt side with the
-respective types. Then the `QVariantList` is returend to Lisp, where it is
+So, we pass a nested Lisp list, and it gets shown on Qt side with the
+respective types. Then the `QVariantList` is returned to Lisp, where it is
 automatically converted back to a nested Lisp list.
 
-Realy convenient!
+Really convenient!