+
+ /**
+ * Given a string, convert it to a (hopefully short) key that can be used
+ * for efficient sorting. A binary sort according to the sortkeys
+ * corresponds to a logical sort of the corresponding strings. Applying
+ * this to cl_raw_sortkey produces cl_sortkey.
+ *
+ * @param string $string UTF-8 string
+ * @return string Binary sortkey
+ */
+ public function convertToSortkey( $string ) {
+ # Stub function for now
+ return $string;
+ }
+
+ /**
+ * Does it make sense for lists to be split up into sections based on their
+ * first letter? Logogram-based scripts probably want to return false.
+ *
+ * TODO: Use this in CategoryPage.php.
+ *
+ * @return boolean
+ */
+ public function usesFirstLettersInLists() {
+ return true;
+ }
+
+ /**
+ * Given a string, return the logical "first letter" to be used for
+ * grouping on category pages and so on. This has to be coordinated
+ * carefully with convertToSortkey(), or else the sorted list might jump
+ * back and forth between the same "initial letters" or other pathological
+ * behavior. For instance, if you just return the first character, but "a"
+ * sorts the same as "A" based on convertToSortkey(), then you might get a
+ * list like
+ *
+ * == A ==
+ * * [[Aardvark]]
+ *
+ * == a ==
+ * * [[antelope]]
+ *
+ * == A ==
+ * * [[Ape]]
+ *
+ * etc., assuming for the sake of argument that $wgCapitalLinks is false.
+ * Obviously, this is ignored if usesFirstLettersInLists() is false.
+ *
+ * @param string $string UTF-8 string
+ * @return string UTF-8 string corresponding to the first letter of input
+ */
+ public function firstLetterForLists( $string ) {
+ return mb_substr( $string, 0, 1 );
+ }