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

Qt_EQL/tutorial/test.cpp

@@ -0,0 +1,37 @@
+#include "test.h"
+#include <QtDebug>
+#include <eql5/eql_fun.h>
+
+Test::Test(QObject* parent, const QString& name) : QObject(parent) {
+    setObjectName(name);
+}
+
+QObject* Test::newInstance(QObject* parent, const QString& name) {
+    return new Test(parent, name);
+}
+
+QString Test::concat(const QStringList& list) {
+    return list.join(", ");
+}
+
+void Test::processData(cl_object data) {
+    // meant for passing complex Lisp data to be processed in C++
+
+    if(cl_listp(data) == ECL_T) {
+        for(cl_object l_dolist = data; cl_car(l_dolist) != ECL_NIL; l_dolist = cl_cdr(l_dolist)) {
+            cl_object l_el = cl_car(l_dolist);
+            cl_print(1, l_el);
+        }
+        cl_terpri(0);
+    }
+}
+
+void Test::printMe() {
+    // you may pass up to 10 arguments of any type found in
+    // '~/eql5/src/ecl_fun.cpp::toMetaArg()', wrapped in macro Q_ARG;
+    // C++ class instances are passed as pointers of a vanilla Qt class
+    // known to EQL5, here: 'QObject*'
+
+    eql_fun("eql-user:print-qt-object", Q_ARG(QObject*, this));
+}
+