static $resumed = false;

	static $resume_stack = array();

	if ( empty($resume_stack) && isset($_POST['resume_stack']) && preg_match('/[a-z_]+((\|[a-z_]+)+)/', $_POST['resume_stack']) )

	{

		$resume_stack = explode('|', $_POST['resume_stack']);

	}

	$already_run = false;

	if ( in_array($stage_id, $resume_stack) )

	{

		$already_run = true;

	}

	if ( !$resumed )

	{

		if ( !isset($_GET['sub']) )

			$resumed = true;

		if ( isset($_GET['sub']) && $_GET['sub'] == $stage_id )

		{

			$resumed = true;

		}

	}

	if ( !$resumed && $allow_skip )

	{

		echo_stage_success($stage_id, $stage_name);

		return false;

	}

	if ( !function_exists($function) )

		die('libenanoinstall: CRITICAL: function "' . $function . '" for ' . $stage_id . ' doesn\'t exist');

	$result = call_user_func($function, false, $already_run);

	if ( $result )

	{

		echo_stage_success($stage_id, $stage_name);

		$resume_stack[] = $stage_id;

		return true;

	}

	else

	{

		echo_stage_failure($stage_id, $stage_name, $failure_explanation, $resume_stack);

		return false;

	}

	echo '<table border="0" cellspacing="0" cellpadding="0" style="margin-top: 10px;">' . "\n";

	echo '</table>' . "\n\n";

	flush();

	global $neutral_color;

	$neutral_color = ( $neutral_color == 'A' ) ? 'C' : 'A';

	echo '<tr><td style="width: 500px; background-color: #' . "{$neutral_color}{$neutral_color}FF{$neutral_color}{$neutral_color}" . '; padding: 0 5px;">' . htmlspecialchars($stage_name) . '</td><td style="padding: 0 5px;"><img alt="Done" src="../images/check.png" /></td></tr>' . "\n";

	flush();

	global $neutral_color;

	global $lang;

	$neutral_color = ( $neutral_color == 'A' ) ? 'C' : 'A';

	echo '<tr><td style="width: 500px; background-color: #' . "FF{$neutral_color}{$neutral_color}{$neutral_color}{$neutral_color}" . '; padding: 0 5px;">' . htmlspecialchars($stage_name) . '</td><td style="padding: 0 5px;"><img alt="Failed" src="../images/checkbad.png" /></td></tr>' . "\n";

	flush();

	close_install_table();

	$post_data = '';

	$mysql_error = mysql_error();

	$file = ( defined('IN_ENANO_UPGRADE') ) ? 'upgrade.php' : 'install.php';

	foreach ( $_POST as $key => $value )

	{

		// FIXME: These should really also be sanitized for double quotes

		$value = htmlspecialchars($value);

		$key = htmlspecialchars($key);

		$post_data .= "          <input type=\"hidden\" name=\"$key\" value=\"$value\" />\n";

	}

	if ( $stage_id == 'renameconfig' )

		echo '<p>' . $failure_explanation . '</p>';

	else

		echo '<form action="' . $file . '?stage=install&amp;sub=' . $stage_id . '" method="post">

						' . $post_data . '

						<input type="hidden" name="resume_stack" value="' . htmlspecialchars(implode('|', $resume_stack)) . '" />

						<h3>' . $lang->get('meta_msg_err_stagefailed_title') . '</h3>

 						<p>' . $failure_explanation . '</p>

 						' . ( !empty($mysql_error) ? "<p>" . $lang->get('meta_msg_err_stagefailed_mysqlerror') . " $mysql_error</p>" : '' ) . '

 						<p>' . $lang->get('meta_msg_err_stagefailed_body') . '</p>

 						<p style="text-align: center;"><input type="submit" value="' . $lang->get('meta_btn_retry_installation') . '" /></p>

					</form>';

	global $ui;

	$ui->show_footer();

	exit;

	global $db, $session, $paths, $template, $plugins; // Common objects

	// Import version info

	global $enano_versions;

	// Import UI functions

	global $ui;

	// This is needed for upgrade abstraction

	global $dbdriver;

	// see if we're actually supposed to be in post-upgrade

	if ( getConfig('enano_version') == 'upg-' . installer_enano_version() )

	{

		// yep, fall out here to avoid errors

		return true;

	}

	// Main upgrade stage

	// Init vars

	list($major_version, $minor_version) = explode('.', installer_enano_version());

	$installer_branch = "$major_version.$minor_version";

	$installer_branch = preg_replace('/^upg-/', '', $installer_branch);

	$target_branch = preg_replace('/^upg-/', '', $target_branch);

	$version_flipped = array_flip($enano_versions[$target_branch]);

	$version_curr = enano_version();

	// Change this to be the last version in the current branch.

	// If we're just upgrading within this branch, use the version the installer library

	// reports to us. Else, use the latest in the old (current target) branch.

	// $version_target = installer_enano_version();

	$version_target = ( $target_branch === $installer_branch ) ? installer_enano_version() : $enano_versions[$target_branch][ count($enano_versions[$target_branch]) - 1 ];

	// Calculate which scripts to run

	if ( !isset($version_flipped[$version_curr]) )

	{

		echo '<p>ERROR: Unsupported version</p>';

		$ui->show_footer();

		exit;

	}

	if ( !isset($version_flipped[$version_target]) )

	{

		echo '<p>ERROR: Upgrader doesn\'t support its own version</p>';

		$ui->show_footer();

		exit;

	}

	$upg_queue = array();

	for ( $i = $version_flipped[$version_curr]; $i < $version_flipped[$version_target]; $i++ )

	{

		if ( !isset($enano_versions[$target_branch][$i + 1]) )

		{

			echo '<p>ERROR: Unsupported intermediate version</p>';

			$ui->show_footer();

			exit;

		}

		$ver_this = $enano_versions[$target_branch][$i];

		$ver_next = $enano_versions[$target_branch][$i + 1];

		$upg_queue[] = array($ver_this, $ver_next);

	}

	// Verify that all upgrade scripts are usable

	foreach ( $upg_queue as $verset )

	{

		$file = ENANO_ROOT . "/install/schemas/upgrade/{$verset[0]}-{$verset[1]}-$dbdriver.sql";

		if ( !file_exists($file) )

		{

			echo "<p>ERROR: Couldn't find required schema file: $file</p>";

			$ui->show_footer();

			exit;

		}

	}

	// Perform upgrade

	foreach ( $upg_queue as $verset )

	{

		$file = ENANO_ROOT . "/install/schemas/upgrade/{$verset[0]}-{$verset[1]}-$dbdriver.sql";

		try

		{

			$parser = new SQL_Parser($file);

		}

		catch(Exception $e)

		{

			die("<pre>$e</pre>");

		}

		$parser->assign_vars(array(

			'TABLE_PREFIX' => table_prefix

		));

		$sql_list = $parser->parse();

		// Check for empty schema file

		if ( $sql_list[0] === ';' && count($sql_list) == 1 )

		{

			// It's empty, report success for this version

			// See below for explanation of why setConfig() is called here

			setConfig('enano_version', $verset[1]);

			continue;

		}

		foreach ( $sql_list as $sql )

		{

			// check for '@' operator on query

			if ( substr($sql, 0, 1) == '@' )

			{

				// Yes - perform query but don't check for errors

				$db->sql_query($sql);

			}

			else

			{

				// Perform as normal

				if ( !$db->sql_query($sql) )

					$db->_die();

			}

		}

		// Is there an additional script (logic) to be run after the schema?

		$postscript = ENANO_ROOT . "/install/schemas/upgrade/{$verset[0]}-{$verset[1]}.php";

		if ( file_exists($postscript) )

			@include($postscript);

		// The advantage of calling setConfig on the system version here?

		// Simple. If the upgrade fails, it will pick up from the last

		// version, not try to start again from the beginning. This will

		// still cause errors in most cases though. Eventually we probably

		// need some sort of query-numbering system that tracks in-progress

		// upgrades.

		setConfig('enano_version', $verset[1]);

	}