Add sidebar to ChangeLog rendering for navigating between versions

Author: sgolemon

ChangeLog-4.php

@@ -3881,4 +3881,6 @@ interface modules (Zeev)</li>
 <li>First public beta of PHP 4.0</li>
 </ul>
 
-<?php site_footer(); ?>
+<?php
+
+site_footer(['sidebar' => changelog_sidebar(4)]);

ChangeLog-5.php

@@ -15957,4 +15957,6 @@ functions if "zend" is specified as the module name. (Ilia)</li>
 </ul>
 <!-- }}} --></section>
 
-<?php site_footer(); ?>
+<?php
+
+site_footer(['sidebar' => changelog_sidebar(5)]);

ChangeLog-7.php

@@ -10231,4 +10231,6 @@
 </ul>
 <!-- }}} --></section>
 
-<?php site_footer(); ?>
+<?php
+
+site_footer(['sidebar' => changelog_sidebar(7)]);

ChangeLog-8.php

@@ -753,4 +753,6 @@
 </ul>
 <!-- }}} --></section>
 
-<?php site_footer();
+<?php
+
+site_footer(['sidebar' => changelog_sidebar(8)]);

include/changelogs.inc

@@ -34,4 +34,15 @@ function release_date($in) {
     echo "<time class='releasedate' datetime='{$for_tools}'>{$human_readable}</time>";
 }
 
-?>
+function changelog_sidebar(?int $current = null): string {
+	$majors = [8, 7, 5, 4];
+	$ret = "<div class=\"panel\">ChangeLogs<div class=\"body\"><ul>\n";
+	foreach ($majors as $major) {
+		if ($major === $current) {
+			$ret .= "  <li><b>PHP {$major}.x</b></li>\n";
+		} else {
+			$ret .= "  <li><a href=\"/ChangeLog-{$major}.php\">PHP {$major}.x</a></li>\n";
+		}
+	}
+	return $ret .= "</ul></body></body>\n";
+}