Add extra example for Collator::getSortKey

Author: derickr

reference/intl/collator/get-sort-key.xml

@@ -66,7 +66,7 @@
   &reftitle.examples;
   <para>
    <example>
-    <title><function>collator_get_sort_key</function>example</title>
+    <title><function>collator_get_sort_key</function> example</title>
     <programlisting role="php">
 <![CDATA[
 <?php
@@ -85,6 +85,76 @@ echo bin2hex($res);
     </screen>
    </example>
   </para>
+
+  <para>
+   <example>
+    <title><function>Collator::getSortKey</function> example with <function>usort</function></title>
+    <programlisting role="php">
+<![CDATA[
+<?php
+$data = [
+    [ 'name' => '🇳🇱 Derick Rethans', 'linked_account' => 'https://phpc.social/users/derickr' ],
+    [ 'name' => 'Elephpant', 'linked_account' => 'https://phpc.social/phpc' ],
+    [ 'name' => '🇫🇷 Marcus Bointon', 'linked_account' => 'https://phpc.social/users/Synchro' ],
+];
+
+/* Create the collator */
+$col = new Collator('en');
+
+/* Sort upper-case letters before lower-case letters */
+$col->setAttribute(Collator::CASE_FIRST, Collator::UPPER_FIRST);
+
+/* Use a user-defined function with sort, that strips out the emojis */
+ */
+usort(
+    $data,
+    function($a, $b) use ($col) {
+        /* Remove the character class 'S' (the Symbols), and remove whitespace
+         * (with trim) */
+        $aName = trim(preg_replace('/\p{S}+/u', '', $a['name']));
+        $bName = trim(preg_replace('/\p{S}+/u', '', $b['name']));
+
+								/* Create the sort key */
+        $aKey = $col->getSortKey($aName);
+        $bKey = $col->getSortKey($bName);
+
+								/* Use the sort key to signal which element sorts first */
+        return $aKey <=> $bKey;
+    }
+);
+
+var_dump($data);
+?>
+]]>
+    </programlisting>
+    &example.outputs.similar;
+    <screen>
+array(3) {
+  [0] =>
+  array(2) {
+    'name' =>
+    string(25) "🇳🇱 Derick Rethans"
+    'linked_account' =>
+    string(33) "https://phpc.social/users/derickr"
+  }
+  [1] =>
+  array(2) {
+    'name' =>
+    string(9) "Elephpant"
+    'linked_account' =>
+    string(24) "https://phpc.social/phpc"
+  }
+  [2] =>
+  array(2) {
+    'name' =>
+    string(25) "🇫🇷 Marcus Bointon"
+    'linked_account' =>
+    string(33) "https://phpc.social/users/Synchro"
+  }
+}
+    </screen>
+   </example>
+  </para>
  </refsect1>
 
  <refsect1 role="seealso">