diff --git a/lib/SearchDescription.php b/lib/SearchDescription.php
index d84c8bf8..533c0ab4 100644
--- a/lib/SearchDescription.php
+++ b/lib/SearchDescription.php
@@ -1,9 +1,9 @@
 <?php
 
-require_once(CONST_BasePath.'/lib/SpecialSearchOperator.php');
-
 namespace Nominatim;
 
+require_once(CONST_BasePath.'/lib/SpecialSearchOperator.php');
+
 /**
  * Description of a single interpretation of a search query.
  */
diff --git a/lib/SpecialSearchOperator.php b/lib/SpecialSearchOperator.php
new file mode 100644
index 00000000..a0ec23e1
--- /dev/null
+++ b/lib/SpecialSearchOperator.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace Nominatim;
+
+/**
+ * Operators describing special searches.
+ */
+abstract class Operator
+{
+    /// No operator selected.
+    const NONE = 0;
+    /// Search for POI of the given type.
+    const TYPE = 1;
+    /// Search for POIs near the given place.
+    const NEAR = 2;
+    /// Search for POIS in the given place.
+    const IN = 3;
+    /// Search for POIS named as given.
+    const NAME = 4;
+    /// Search for postcodes.
+    const POSTCODE = 5;
+
+    private static $aConstantNames = null;
+
+
+    public static function toString($iOperator)
+    {
+        if ($iOperator == Operator::NONE) {
+            return '';
+        }
+
+        if (Operator::$aConstantNames === null) {
+            $oReflector = new \ReflectionClass('Nominatim\Operator');
+            $aConstants = $oReflector->getConstants();
+
+            Operator::$aConstantNames = array();
+            foreach ($aConstants as $sName => $iValue) {
+                Operator::$aConstantNames[$iValue] = $sName;
+            }
+        }
+
+        return Operator::$aConstantNames[$iOperator];
+    }
+}