Progress on VUFIND-505: created mechanism to allow more complex checkbox filters.

config/vufind/searches.ini

@@ -192,6 +192,9 @@ CallNumber = callnumber
 ;       standard facet settings (defaults to "Results" if not specified),
 ;       and [checkbox facet section] is the name of a section of the ini file
 ;       containing checkbox facet settings (leave blank for no checkbox facets).
+;       Checkbox facets are normally in filter => label format; prefix the section
+;       name with ~ to reverse this and use label => filter format (useful if your
+;       filters contain values that are illegal in configuration keys -- e.g. []).
 ; SummonDatabases:[GET parameter]
 ;       Display Summon-generated database recommendations matching the terms found
 ;       in the specified GET parameter.  NOTE: If you are using this module with a

module/VuFind/src/VuFind/Recommend/SideFacets.php

@@ -77,9 +77,16 @@ class SideFacets implements RecommendInterface
         }
 
         // Checkbox facets:
+        if (substr($checkboxSection, 0, 1) == '~') {
+            $checkboxSection = substr($checkboxSection, 1);
+            $flipCheckboxes = true;
+        }
         $this->checkboxFacets
             = ($checkboxSection && isset($config->$checkboxSection))
             ? $config->$checkboxSection->toArray() : array();
+        if ($flipCheckboxes) {
+            $this->checkboxFacets = array_flip($this->checkboxFacets);
+        }
     }
 
     /**