Index: lib/moodlelib.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/moodlelib.php,v
retrieving revision 1.960.2.15
diff -u -r1.960.2.15 moodlelib.php
--- lib/moodlelib.php	4 Dec 2007 11:46:12 -0000	1.960.2.15
+++ lib/moodlelib.php	6 Dec 2007 15:45:06 -0000
@@ -5019,7 +5019,7 @@
     foreach ($locations as $location) {
         $locallangfile = $location.$lang.'_local'.'/'.$module.'.php';    //first, see if there's a local file
         if (file_exists($locallangfile)) {
-            if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring")) {
+            if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring", $a)) {
                 eval($result);
                 return $resultstring;
             }
@@ -5027,7 +5027,7 @@
         //if local directory not found, or particular string does not exist in local direcotry
         $langfile = $location.$lang.'/'.$module.'.php';
         if (file_exists($langfile)) {
-            if ($result = get_string_from_file($identifier, $langfile, "\$resultstring")) {
+            if ($result = get_string_from_file($identifier, $langfile, "\$resultstring", $a)) {
                 eval($result);
                 return $resultstring;
             }
@@ -5045,14 +5045,14 @@
     foreach ($locations as $location) {
         $langfile = $location.$lang.'/'.$filetocheck;
         if (file_exists($langfile)) {
-            if ($result = get_string_from_file('parentlanguage', $langfile, "\$parentlang")) {
+            if ($result = get_string_from_file('parentlanguage', $langfile, "\$parentlang", $a)) {
                 eval($result);
                 if (!empty($parentlang)) {   // found it!
 
                     //first, see if there's a local file for parent
                     $locallangfile = $location.$parentlang.'_local'.'/'.$module.'.php';
                     if (file_exists($locallangfile)) {
-                        if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring")) {
+                        if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring", $a)) {
                             eval($result);
                             return $resultstring;
                         }
@@ -5061,7 +5061,7 @@
                     //if local directory not found, or particular string does not exist in local direcotry
                     $langfile = $location.$parentlang.'/'.$module.'.php';
                     if (file_exists($langfile)) {
-                        if ($result = get_string_from_file($identifier, $langfile, "\$resultstring")) {
+                        if ($result = get_string_from_file($identifier, $langfile, "\$resultstring", $a)) {
                             eval($result);
                             return $resultstring;
                         }
@@ -5076,7 +5076,7 @@
     foreach ($locations as $location) {
         $locallangfile = $location.$defaultlang.'_local/'.$module.'.php';    //first, see if there's a local file
         if (file_exists($locallangfile)) {
-            if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring")) {
+            if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring", $a)) {
                 eval($result);
                 return $resultstring;
             }
@@ -5086,7 +5086,7 @@
         $langfile = $location.$defaultlang.'/'.$module.'.php';
 
         if (file_exists($langfile)) {
-            if ($result = get_string_from_file($identifier, $langfile, "\$resultstring")) {
+            if ($result = get_string_from_file($identifier, $langfile, "\$resultstring", $a)) {
                 eval($result);
                 return $resultstring;
             }
@@ -5100,7 +5100,7 @@
         foreach ($locations as $location) {
             $locallangfile = $location.$defaultlang.'_local/'.$module.'.php';    //first, see if there's a local file
             if (file_exists($locallangfile)) {
-                if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring")) {
+                if ($result = get_string_from_file($identifier, $locallangfile, "\$resultstring", $a)) {
                     eval($result);
                     return $resultstring;
                 }
@@ -5110,7 +5110,7 @@
             $langfile = $location.$defaultlang.'/'.$module.'.php';
 
             if (file_exists($langfile)) {
-                if ($result = get_string_from_file($identifier, $langfile, "\$resultstring")) {
+                if ($result = get_string_from_file($identifier, $langfile, "\$resultstring", $a)) {
                     eval($result);
                     return $resultstring;
                 }
@@ -5128,17 +5128,19 @@
  * @param string $identifier ?
  * @param string $langfile ?
  * @param string $destination ?
+ * @param mixed $a Arbitrary parameter to get_string, used only for expressions
  * @return string|false ?
  * @staticvar array $strings Localized strings
  * @access private
  * @todo Finish documenting this function.
  */
-function get_string_from_file($identifier, $langfile, $destination) {
+function get_string_from_file($identifier, $langfile, $destination, $a) {
 
     static $strings;    // Keep the strings cached in memory.
 
     if (empty($strings[$langfile])) {
         $string = array();
+        $string19 =& $string;
         include ($langfile);
         $strings[$langfile] = $string;
     } else {
@@ -5148,8 +5150,28 @@
     if (!isset ($string[$identifier])) {
         return false;
     }
+        
+    // When the string is actually an array, it should be an associative array
+    // where the keys are PHP expressions and values are language strings as
+    // normal. Expressions are tested in order and for the first matching one,
+    // the language string is returned. 
+    if(is_array($string[$identifier])) {
+        $selectedstring=null;
+        foreach($string[$identifier] as $expression=>$value) {
+            if($expression==='' || eval("return $expression;")) {
+                $selectedstring=$value;
+                break;                
+            }
+        }
+        if($selectedstring===null) {
+            debugging("No matching expression for language string $identifier");
+            return false;
+        }    
+    } else {
+        $selectedstring=$string[$identifier];
+    }
 
-    return $destination .'= sprintf("'. $string[$identifier] .'");';
+    return $destination .'= sprintf("'. $selectedstring .'");';
 }
 
 /**