sorting concept property values with natural case sort when sortByNot…

…ation is true, fixes #737

model/Concept.php

@@ -533,7 +533,8 @@ public function getProperties()
                 if ($superprop) {
                     $superprop = EasyRdf\RdfNamespace::shorten($superprop) ? EasyRdf\RdfNamespace::shorten($superprop) : $superprop;
                 }
-                $propobj = new ConceptProperty($prop, $proplabel, $superprop);
+                $notsort = $this->vocab->getConfig()->sortByNotation();
+                $propobj = new ConceptProperty($prop, $proplabel, $superprop, $notsort);
 
                 if ($propobj->getLabel() !== null) {
                     // only display properties for which we have a label

model/ConceptProperty.php

@@ -15,19 +15,21 @@ class ConceptProperty
     private $values;
     /** flag whether the values are sorted, as we do lazy sorting */
     private $is_sorted;
+    private $sort_by_notation;
 
     /**
      * Label parameter seems to be optional in this phase.
      * @param string $prop property type eg. 'rdf:type'.
      * @param string $label
      */
-    public function __construct($prop, $label, $super=null)
+    public function __construct($prop, $label, $super=null, $notsort=false)
     {
         $this->prop = $prop;
         $this->label = $label;
         $this->values = array();
         $this->is_sorted = true;
         $this->super = $super;
+        $this->sort_by_notation = $notsort;
     }
 
     /**
@@ -86,7 +88,7 @@ private function sortValues()
     {
         if (!empty($this->values)) {
             uksort($this->values, function($a, $b) {
-                return strcoll(strtolower($a),strtolower($b));
+                return $this->sort_by_notation ? strnatcasecmp($a, $b) : strcoll(strtolower($a),strtolower($b));
             });
         }
         $this->is_sorted = true;