explain results for Geocode::lookup()

lib/Geocode.php

@@ -309,6 +309,36 @@ function getDetails($aPlaceIDs)
 			return $aSearchResults;
 		}
 
+        /* Perform the actual query lookup.
+
+           Returns an ordered list of results, each with the following fields:
+              osm_type:   type of corresponding OSM object
+                            N - node
+                            W - way
+                            R - relation
+                            P - postcode (internally computed)
+              osm_id: id of corresponding OSM object
+              class: general object class (corresponds to tag key of primary OSM tag)
+              type: subclass of object (corresponds to tag value of primary OSM tag)
+              admin_level:  see http://wiki.openstreetmap.org/wiki/Admin_level
+              rank_search:  rank in search hierarchy
+                            (see also http://wiki.openstreetmap.org/wiki/Nominatim/Development_overview#Country_to_street_level)
+              rank_address: rank in address hierarchy (determines orer in address)
+              place_id: internal key (may differ between different instances)
+              country_code: ISO country code
+              langaddress: localized full address
+              placename: localized name of object
+              ref: content of ref tag (if available)
+              lon: longitude
+              lat: latitude
+              importance: importance of place based on Wikipedia link count
+              addressimportance: cumulated importance of address elements
+              extra_place: type of place (for admin boundaries, if there is a place tag)
+              aBoundingBox: bounding Box
+              label: short description of the object class/type (English only) 
+              name: full name (currently the same as langaddress)
+              foundorder: further ordering value for places with same importance
+         */
 		function lookup()
 		{
 			if (!$this->sQuery && !$this->aStructuredQuery) return false;