add new function QVARIANT-FROM-VALUE, needed in QML:QML-SET ("quick" examples)

examples/M-modules/quick/qml-lisp/example.lisp

@@ -8,6 +8,7 @@
 (require :qml-lisp "qml-lisp")
 
 (defun run ()
+  ;; *quick-view* can be either a QQuickView or a QQuickWidget
   (setf qml:*quick-view* (qnew "QQuickView(QUrl)"
                                (|fromLocalFile.QUrl| "qml/example.qml")))
   (|setResizeMode| qml:*quick-view* |QQuickView.SizeRootObjectToView|)

examples/M-modules/quick/qml-lisp/qml-lisp.lisp

@@ -100,7 +100,7 @@
                    (find-qml-object object-name)
                    property-name))
     (x:when-it (|propertyTypeName| property)
-      (qlet ((variant (qnew (format nil "QVariant(~A)" x:it) value)))
+      (qlet ((variant (qvariant-from-value value x:it)))
         (|write| property variant)))))
 
 ;;; JS