Bearbeiten von „ProcessWire - Navigation Snippets“

== TODO Seite aufräumen ==
== Navigation in Pagewire - Einführung ==
=== Navigationstypen allgemein ===
Es gibt verschiedene '''Typen von Navigationen'''. In Processwire hat man ein '''Pages Objekt''', indem auch Zugriff auf Kind- und Elternseiten möglich sind. Es bildet also immer die Sitestruktur ab. Daher übergibt man an die unten aufgeführten Funktionen entweder die Homepage oder die aktuelle Seite.

Unter dem Aspekt auf welcher Seite man sich befindet kann man unterscheiden zwischen:
* '''absolute Navigation''' normalerweise ausgehend von der Rootseite. diese ist dann auf allen Seiten gleich.
** z.B. alle Seiten des ersten Levels stehen in der Hauptnavigation egal auf welcher Seite ich im Moment bin
** z.B. verschachtelte Liste mit 2 oder mehr Leveln für Dropdown Navigationen wie Superfish, Megamenüs (mit zusätzlichen Infos...) oder Bootstrap Navigationen.
** Sitemap
* '''Navigation relativ zur Seite''' Diese kann sich von Seite zu Seite unterscheiden.
** Alle '''Seiten der aktuellen Ebene''' (oft kombiniert mit Breadcrumb / Hier-bin-ich) ) 
** Hauptebene '''und''' aktueller Level
** Alle Ebenen '''bis zur aktuellen Seite + deren Unterseiten''' falls vorhanden. 
In letzten Fall könnte man auch Varianten bauen in denen eine Verschachtelte Liste erzeugt wird aber nur bestimmte Teile absolut Positioniert angezeigt werden und andere versteckt werden. Manchmal möchte man bestimmte Level aber auch an anderer Position zeigen (z.B. Sidebar)
In der Praxis hat man in der Regel
* Mindestens eine Hauptnavigation mit allen Seiten der 1. Ebene oder eine Hauptnavigation mit mehreren Ebenen für Dropdown Navigationen, mobile Navigation oder auch Sitemapartige Navigationen für den Footer (oft mit kleinen Beschreibungen).
* Eine Metanavigation mit Service Seiten wie Kontakt, Impressum etc. oft ist diese im Footer.

=== Unterschiede zwischen Verstecken, Veröffentlichen, Sperren ===
In Processwire sind diese Begriffe mit Userrechten verknüpft. Eine unveröffentlichte Seite kann also durchaus im Frontend aufgerufen werden (es sei denn man regelt das anders.) Vielmehr geht es darum das man User Rollen so gestalten kann, dass man z.B. einem User nur erlaubt unveröffentlichte Seiten zu editieren.

Denoch gibt es auch ein paar weitere Unterschiede.

Gesperrt -> Man kann die Seite nicht zum Editieren aufrufen. Über die Url kann Sie aufgerufen werden.

Unpublished -> Die Seite kann sobald sie gespeichert ist auch aufgerufen werden, WENN der User berechtigt ist. Nicht für Guest User (der normale Viewer)

TODO checken ob die Tabelle so für nicht angemeldete User stimmt.
{| class="wikitable"
|-
!  !! Im Menü ($pages->find) !! Über URL ($pages->get)
|-
| Unpublished / Unveröffentlicht || Nein || Nur User mit passenden Rechten 
|-
| Hidden / Versteckt || Nein || Ja 
|-
| Locked / Gesperrt || Ja || Ja  
|-
| Trash || Nein || Nein 
|}
==== Seiten auf unveröffentlicht stellen ====
https://processwire.com/talk/topic/29-how-to-unpublish-a-page-without-deleting-it/

Was soll man tun wenn man eine Seite tatsächlich nicht mehr anzeigen will, sie aber noch nicht wegwerfen will?
Ryan schlägt folgendes vor:
* Mülleimer
* Remove Guest Role
*

== Basics ==

=== Page Level ===
In which level in page tree we are?
 $level = count($page->parents);

=== Link to Subpage und Platzhalter (Spacer) ===
Kann man gut für Superfish Menüs etc. benutzen. Bildet das Verhalten von Shortcuts und Spacern aus TYPO3 nach.

Anpassung der renderNavTree() Funktion von Ryan Cramer. Options Field Installieren und als globales Feld "navigation_type" mit den Optionen 
<pre>
1=normal|Normal
2=doNotLink|Do not link
3=linkToFirstChild|Link to first childpage
</pre>
konfigurieren. Dann Funktion etwa so anpassen:
<pre>
...
// cycle through all the items
	foreach($items as $item) {

		// markup for the list item...
		// if current item is the same as the page being viewed, add a "current" class to it
		$out .= $item->id == wire('page')->id ? "<li class='current'>" : "<li>";

		// markup for the link
		$navigation_type = $item->navigation_type->id;
		switch ( $navigation_type ) {
			case 2: // do not link
				$out .= "<span class='spacer'>$item->title</span>";
				break;
			case 3: // link to subpage
				if( $item->hasChildren() ){
					$out .= '<a href="'.$item->child->url.'">'.$item->title.'</a>';
				}else{
					$out .= "<span class='spacer'>$item->title</span>";
				}
				break;
			default:
				$out .= "<a href='$item->url'>$item->title</a>";
				break;
		}
...
</pre>

=== Redirect (301) ===
==== Redirect zu erster Unterseite ====
https://processwire.com/talk/topic/15-how-do-i-create-a-page-that-redirects-to-its-first-child/

Field ''redirects_to_first_child'' erstellen und im Template einfügen.
<syntaxhighlight lang="php">
<?php 
  if($page->numChildren && $page->redirects_to_first_child) 
  $session->redirect($page->child()->url); 
?>
</syntaxhighlight>
Erzeugt 301 Weiterleitung

Anderer Ansatz wäre evtl. den Link bei der Menügenerierung direkt zu generieren. finde ich persönlich besser siehe ''Link to subpage und Platzhalter'' Beispiel. Allerdings sollte man dann vielleicht die Seite trotzdem per 301 Weiterleiten, falls die URL mal direkt aufgerufen wird oder bei Google gelistet ist.

==== Redirect zu anderer Seite in der Navigation ====
https://processwire.com/talk/topic/762-howto-menu-item-that-links-to-another-page/

1. Create a new field and call it 'redirect_url' or something like that, and use the 'URL' fieldtype. 

2. Add that field to your template where you'd want to use it, or create a new template just for the purpose, like a template named 'redirect'.

3. Edit the page that you want to be a symlink and populate the 'redirect_url' field with the URL you want it to redirect to.

4. In your nav-generation code that links to the pages, do something like this:

<syntaxhighlight lang="php">
<?php
$url = $subpage->get("redirect_url|url"); // use redirect_url if there, otherwise use url
echo "<a href='$url'>{$subpage->title}</a>";
</syntaxhighlight>
5. You might also want to add this to your template that has the 'redirect_url' field: just in case there's anything linking to it directly. That way it'll send people to the right place either way:

 <?php
 if($page->redirect_url) $session->redirect($page->redirect_url); 

=== Breadcrumb ===
<pre>
	<!-- breadcrumbs -->
	<div class='breadcrumbs'><?php 
		// breadcrumbs are the current page's parents
		foreach($page->parents() as $item) {
			echo "<span><a href='$item->url'>$item->title</a></span> "; 
		}
		// optionally output the current page as the last item
		echo "<span>$page->title</span> "; 
	?></div>
</pre>

=== One Level Navigation Bar ===
[[ProcessWire - One Level Navigation]]
=== Nächste Seite / Next Page Navigation ===
<syntaxhighlight lang="php">
if($page->next->id){
  $next = '
    <div class="next">
      <i>Next:</i>&nbsp;
      <a class="ajax-link" name="'.$page->next->title.'" href="'. $page->next->url .'">
        '. $page->next->title .'<span class="fa fa-arrow-right"><span>
      </a>
    </div>';
}
</syntaxhighlight>

=== Zurück zur Elternseite ===
<syntaxhighlight lang="php">
<div class="back"><a href="'.$page->parent()->url.'">zurück</a></div>
</syntaxhighlight>

=== Kindseiten mit $page->children ===
 <?=$page->children?>
Output
 5723,4958,5937

Beispiel
<syntaxhighlight lang="php">
<ul>
<?php
foreach($page->children as $child)
  echo "<li><a href='{$child->url}'>{$child->title}</a></li>";
?> 
</ul>
</syntaxhighlight>
Ergebnis:
<pre>
<ul> 
<li><a href='/about/contact/'>Contact Us</a></li>
<li><a href='/about/press/'>Press Releases</a></li>
<li><a href='/about/staff/'>Our Staff</a></li> 
</ul>
</pre>
=== Children Tree ===
<syntaxhighlight lang="php">
function listChildrenTree($children, $current, $w) {

echo "<ul>";

foreach($children as $page) {

	$class = '';
	if($page === $current || $current->parents->slice(1)->has($page) ) {
		$class = "class='on' style='font-weight:bold'";
	}

	$rootid = $w->pages->get("/")->id;

	echo "<li><a href='{$page->url}' $class>";
	if($page->id == $rootid) echo "<img src='" . $w->config->urls->templates . "styles/images/home.png' width='24' height='28' alt='' />";
	echo "{$page->title}</a> ";

	if($page->numChildren && $page->id != $rootid) listChildrenTree($page->children, $current, $w);

	echo "</li>";
}
echo "</ul>";
}

$children = $pages->get("/")->children();
$children->prepend($pages->get("/"));

listChildrenTree($children, $page, $wire);
</syntaxhighlight>

== Bootstrap Navigation ==
<syntaxhighlight lang="php">
<?php namespace ProcessWire;
// Markup to use wicht navigation_type field (normal=1, no-link=2,subpage=3)
?>

<?php

// bundle up the first level pages and prepend the root home page
$homepage = $pages->get(1);
$pa = $homepage->children;
$pa = $pa->prepend($homepage);

// Set the ball rolling...
$myMenu = renderChildrenOf($pa);
$wrapper = '
<nav class="navbar navbar-default">
  <div class="container-fluid">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar-collapse-1" aria-expanded="false">
        <span class="sr-only">Menü</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
    </div>
    <div class="collapse navbar-collapse" id="navbar-collapse-1">
      |
    </div>
  </div>
</div>';
$myMenu = wrap($myMenu,$wrapper);
echo $myMenu;

/*
Navigation for ProcessWire using the Bootstrap 2.2.2 markup
This menu was written by Soma based on work by NetCarver and a bit thrown in by Joss
Bootstrap 3 update by Damienov, with multi level dropdown support fix
*/
function renderChildrenOf($pa, $output = '', $level = 0)
{
    $output = '';
    $level++;

    foreach ($pa as $child) {
        $atoggle = '';
        $class = '';

        if ($child->numChildren && count($child->parents) == 1) {
            $class .= 'dropdown';
            $atoggle .= ' class="dropdown-toggle" data-toggle="dropdown"';
        } else if ($child->numChildren && count($child->parents) > 1 ) {
            $class .= 'dropdown-submenu';
            $atoggle .= ' class="dropdown-toggle"';
        } else if ($child->numChildren && $child->id != 1) {
            $class .= 'dropdown-menu';
        }

        // Makes the current page and it's top level parent add an active class
        $class .= ($child === wire("page") || $child === wire("page")->rootParent) ? " active" : '';
        $class = strlen($class) ? " class='" . trim($class) . "'" : '';

        if ($child->numChildren && count($child->parents) == 1) {
            // Add Caret if have children
            $output .= "<li$class><a href='$child->url'$atoggle>$child->title <b class='caret'></b></a>";
        } else if ($child->numChildren && count($child->parents) > 1) {
            $output .= "<li$class><a tabindex='-1' href='$child->url'$atoggle>$child->title</a>";
        } else {
            $output .= "<li$class><a href='$child->url'$atoggle>$child->title</a>";
        }

        // If this child is itself a parent and not the root page, then render it's children in their own menu too...
        if ($child->numChildren && $child->id != 1) {
            $output .= renderChildrenOf($child->children, $output, $level);
        }
        $output .= '</li>';
    }
    $outerclass = ($level == 1) ? "nav navbar-nav" : 'dropdown-menu';
    return "<ul class='$outerclass'>$output</ul>";
}

?>
</syntaxhighlight>

== Modul: MarkupSimpleNavigation==
[[Processwire Modul - MarkupSimpleNavigation]]

== Weitere Menübeispiele ==
=== Standard Tree Navigation ===
Für viele Zwecke ausreichend und leicht anpassbar, die klassische verschachtelte Liste.



=== Menüauswahl Hauptmenü / Metamenü / Footer-Navigation ===
Beispiel 1
Backend Feld menus anlegen Options: 

 1=Main Menu
 2=Meta Menu 

topnav.inc
<syntaxhighlight lang="php">
$pa = $homepage->and($homepage->children("menus.id=1"));//only if main menu is checked
$options = array('level' => '1', 'ulClass' => 'sf-menu', 'liClass' => '');
echo "<div>".renderNavTreeType($pa, $maxDepth = 1, $fieldNames = '', $options)."</div>";
</syntaxhighlight>


'''Beispiel 2 (älter)'''

Checkbox anlegen (footer_nav), und dann das Seitenarray etwa so modifizieren.
<pre>
$footer_nav = $pages->find("parent=1, footer_checkbox=1");
$main_nav = $pages->find("parent=1, footer_checkbox!=1");
</pre>

=== Zweispaltige Navigation aus Kindseiten ===
Verbesserungsvorschlag: Anstatt if lieber zwei for Schleifen -> bessere Performance
<syntaxhighlight lang="php">
// Childrens
$n = count($page->children);
$m = ceil($n/2);
$c = 0;

// NAVIGATION & SLIDER Items
$listItem = '';
$navList = '';
$col1 = '<ul class="nav-list col1">';
$col2 = '<ul class="nav-list col2">';
foreach ($page->children as $item) {
	if($item->id == $page->rootParent->id) {
		$listItem = '<li class="current">';
	} else {
		$listItem = '<li>';
	}
	$listItem .= '<a class="ajax-link" href="'.$item->url.'">'.$item->title.'</a></li>';
	($c < $m) ? $col1 .= $listItem : $col2 .= $listItem;
	$c++;
}
$col1 .= '</ul>';
$col1 .= '</ul>';
$navList = $col1.$col2;
</syntaxhighlight>

=== Pushy Menu ===
<syntaxhighlight lang="php">
/**
 * Given a group of pages, render a <ul> navigation tree
 *
 * This is here to demonstrate an example of a more intermediate level
 * shared function and usage is completely optional. This is very similar to
 * the renderNav() function above except that it can output more than one
 * level of navigation (recursively) and can include other fields in the output.
 * Assumes there is a field navigation_type to decide how a list item is
 * rendered
 *
 * @param array|PageArray $items
 * @param int $maxDepth How many levels of navigation below current should it go?
 * @param string $fieldNames Any extra field names to display (separate multiple fields with a space)
 * @param array $options extra options for classes configuration etc.
 * @return string
 *
 */
function renderPushyMenu($items, $maxDepth = 0, $fieldNames = '', $options = array('level' => 0, 'ulClass' => '', 'liClass' => '', 'aClass' => '') ) {

	// if we were given a single Page rather than a group of them, we'll pretend they
	// gave us a group of them (a group/array of 1)
	if($items instanceof Page) $items = array($items);
	$out = '';
  $c = 0;
  $liClasses = array();
  $ulClasses = array();
	$level = 0;
	$liClass = '';
	$ulClass = '';

	if(!empty($options['level'])) $level = $options['level'];
	if(!empty($options['ulClass'])) {
		$ulClasses[] = $options['ulClass'];
		$ulClass = $options['ulClass'];
	}

	if(!empty($options['liClass'])) {
		$liClasses[] = $options['liClass'];
		$liClass = $options['liClass'];
	}

	// cycle through all the items
	foreach($items as $item) {
    //$level = count($page->parents);
		// LI ITEM
		$classes = $liClasses;
    //if($item->id == wire('page')->id) $classes[] = 'cur';
		if($item->hasChildren) {
      // BUTTON instead of Link
      $out .= '<li class="pushy-submenu"><button>'.$item->title.'</button>';
		}else{
      $classes[] = 'level-'.$level;
  		$out .= '<li class="'.implode($classes,' ').'">';
      unset($classes);

  		// A ITEM
  		$navigation_type = $item->navigation_type->id;
  		$classes = $liClasses;
  		switch ( $navigation_type ) {
  			case 2: // do not link
  				$out .= '<span class="spacer">'.$item->title.'</span>';
  				break;
  			case 3: // link to subpage
  				if( $item->hasChildren() ){
  					$out .= '<a href="'.$item->child->url.'" class="ajax-link">'.$item->title.'</a>';
  				}else{
  					$out .= "<span class='spacer'>$item->title</span>";
  				}
  				break;
  			default:
  				$out .= '<a href="'.$item->url.'" class="ajax-link">'.$item->title.'</a>';
  				break;
  		}
  		unset($classes);
		}
		// if there are extra field names specified, render markup for each one in a <div>
		// having a class name the same as the field name
		if($fieldNames) foreach(explode(' ', $fieldNames) as $fieldName) {
			$value = $item->get($fieldName);
			if($value) $out .= " <div class='$fieldName'>$value</div>";
		}

		// if the item has children and we're allowed to output tree navigation (maxDepth)
		// then call this same function again for the item's children
		if($item->hasChildren() && $maxDepth) {
			//if($class == 'nav') $class = 'nav nav-tree';
			$nextLevelOptions = array('level' => $level+1, 'ulClass' => '', 'liClass' => $liClass);
			$out .= renderNavTreeType($item->children, $maxDepth-1, $fieldNames, $nextLevelOptions);
		}

		// close the list item
		$out .= "</li>\n";
	}

	// if output was generated above, wrap it in a <ul>

	if($out) $out = "\n".'<ul class="'.implode($ulClasses,' ').'">'."\n".$out.'</ul>'."\n";

	// return the markup we generated above
	return $out;
}

</syntaxhighlight>

== Do not link / link to subpage ==
Zusätzliches Feld (Options) im Backend mit Namen navigation_type

Beispiel
<syntaxhighlight lang="php">
/**
 * Given a group of pages, render a <ul> navigation tree
 * If there is a field navigation_type the vals have following meaning
 * 1 = Normal
 * 2 = Do not link
 * 3 = Link to subpage
 *
 * @param array|PageArray $items
 * @param int $maxDepth How many levels of navigation below current should it go?
 * @param string $fieldNames Any extra field names to display (separate multiple fields with a space)
 * @param string $class CSS class name for containing <ul>
 * @return string
 *
 */
function renderNavTreeType($items, $maxDepth = 0, $fieldNames = '', $options = array('level' => 0, 'ulClass' => 'nav', 'liClass' => '', 'aClass' => '') ) {

	// if we were given a single Page rather than a group of them, we'll pretend they
	// gave us a group of them (a group/array of 1)
	if($items instanceof Page) $items = array($items);

	// $out is where we store the markup we are creating in this function
	$out = '';
  $c = 0;
  $liClasses = array();
  $ulClasses = array();
	$level = 0;
	$liClass = '';
	$ulClass = '';

	if(!empty($options['level'])) $level = $options['level'];
	if(!empty($options['ulClass'])) {
		$ulClasses[] = $options['ulClass'];
		$ulClass = $options['ulClass'];
	}

	if(!empty($options['liClass'])) {
		$liClasses[] = $options['liClass'];
		$liClass = $options['liClass'];
	}

	// cycle through all the items
	foreach($items as $item) {
    //$level = count($page->parents);
		// LI ITEM
		$classes = $liClasses;
    if($item->id == wire('page')->id) $classes[] = 'cur';
		if($item->hasChildren) $classes[] = 'has_children';
    $classes[] = 'level-'.$level;
		$out .= '<li class="'.implode($classes,' ').'">';
    unset($classes);

		// markup for the link
		$navigation_type = $item->navigation_type->id;
		$classes = $liClasses;
		switch ( $navigation_type ) {
			case 2: // do not link
				$out .= '<span class="spacer">'.$item->title.'</span>';
				break;
			case 3: // link to subpage
				if( $item->hasChildren() ){
					$out .= '<a href="'.$item->child->url.'" class="ajax-link">'.$item->title.'</a>';
				}else{
					$out .= "<span class='spacer'>$item->title</span>";
				}
				break;
			default:
				$out .= '<a href="'.$item->url.'" class="ajax-link">'.$item->title.'</a>';
				break;
		}
		unset($classes);
		// if there are extra field names specified, render markup for each one in a <div>
		// having a class name the same as the field name
		if($fieldNames) foreach(explode(' ', $fieldNames) as $fieldName) {
			$value = $item->get($fieldName);
			if($value) $out .= " <div class='$fieldName'>$value</div>";
		}

		// if the item has children and we're allowed to output tree navigation (maxDepth)
		// then call this same function again for the item's children
		if($item->hasChildren() && $maxDepth) {
			//if($class == 'nav') $class = 'nav nav-tree';
			$nextLevelOptions = array('level' => $level+1, 'ulClass' => '', 'liClass' => $liClass);
			$out .= renderNavTreeType($item->children, $maxDepth-1, $fieldNames, $nextLevelOptions);
		}

		// close the list item
		$out .= "</li>\n";
	}

	// if output was generated above, wrap it in a <ul>

	if($out) $out = "\n".'<ul class="'.implode($ulClasses,' ').'">'."\n".$out.'</ul>'."\n";

	// return the markup we generated above
	return $out;
}
</syntaxhighlight>

== Beispiele für Funktionen (z.B. in _func.php)==
'''Beispiele für Funktionen die Navigationen erzeugen. '''
=== One Level ===
==== Original ProcessWire Demo Beispiel ====



=== Nested List ausgehend von einer Seite (meistens Homepage) ===
<syntaxhighlight lang="php">
<?php namespace ProcessWire;

 /**
  * Given a group of pages, render a one level navbar
  *
  * @param array|PageArray $items
  * @return string
  *
  */
 function renderNavMain($pa,$pageId){
   if($pa instanceof Page) $pa = array($pa);
   $out = '<nav class="menu menu--ferdinand"><ul class="nav navbar-nav menu__list">';
   foreach($pa as $item) {
     if($item->id == $pageId) {
       $out .= "<li class=\"menu__item menu__item--current cur\">";
     } else {
       $out .= "<li class=\"menu__item\">";
     }
     // if template isotope-parent add first isotope-child name as hash
     if($item->template->name == 'isotope-parent'){
       $out .= '<a class="menu__link" href="'.$item->url.'#'.$item->child->name.'">'.$item->title.'</a></li>';
     }else $out .= '<a class="menu__link" href="'.$item->url.'">'.$item->title.'</a></li>';
   }
     $out .= "</ul></nav>";
     return $out;
 }

 function renderNavIsotope($pa){
   if($pa instanceof Page) $pa = array($pa);
   $out = '<ul class="submenu">';
   foreach($pa as $item){
     $out .= '<li><a href="#'.$item->name.'" class="isotope-link">'.$item->title.'</a></li>';
   }
   $out .= "</ul>";
   return $out;
 }


/**
 * Given a group of pages, render a simple <ul> navigation
 *
 * This is here to demonstrate an example of a simple shared function.
 * Usage is completely optional.
 *
 * @param PageArray $items
 * @return string
 *
 */
function renderNav(PageArray $items) {

	// $out is where we store the markup we are creating in this function
	$out = '';

	// cycle through all the items
	foreach($items as $item) {

		// render markup for each navigation item as an <li>
		if($item->id == wire('page')->id) {
			// if current item is the same as the page being viewed, add a "current" class to it
			$out .= "<li class='current'>";
		} else {
			// otherwise just a regular list item
			$out .= "<li>";
		}

		// markup for the link
		$out .= "<a href='$item->url'>$item->title</a> ";

		// if the item has summary text, include that too
		if($item->summary) $out .= "<div class='summary'>$item->summary</div>";

		// close the list item
		$out .= "</li>";
	}

	// if output was generated above, wrap it in a <ul>
	if($out) $out = "<ul class='nav'>$out</ul>\n";

	// return the markup we generated above
	return $out;
}



/**
 * Given a group of pages, render a <ul> navigation tree
 *
 * This is here to demonstrate an example of a more intermediate level
 * shared function and usage is completely optional. This is very similar to
 * the renderNav() function above except that it can output more than one
 * level of navigation (recursively) and can include other fields in the output.
 *
 * @param array|PageArray $items
 * @param int $maxDepth How many levels of navigation below current should it go?
 * @param string $fieldNames Any extra field names to display (separate multiple fields with a space)
 * @param string $class CSS class name for containing <ul>
 * @return string
 *
 */
function renderNavTree($items, $maxDepth = 0, $fieldNames = '', $class = 'nav') {

	// if we were given a single Page rather than a group of them, we'll pretend they
	// gave us a group of them (a group/array of 1)
	if($items instanceof Page) $items = array($items);

	// $out is where we store the markup we are creating in this function
	$out = '';

	// cycle through all the items
	foreach($items as $item) {

		// markup for the list item...
		// if current item is the same as the page being viewed, add a "current" class to it
		$out .= $item->id == wire('page')->id ? "<li class='current'>" : "<li>";

		// markup for the link
		$out .= "<a href='$item->url'>$item->title</a>";

		// if there are extra field names specified, render markup for each one in a <div>
		// having a class name the same as the field name
		if($fieldNames) foreach(explode(' ', $fieldNames) as $fieldName) {
			$value = $item->get($fieldName);
			if($value) $out .= " <div class='$fieldName'>$value</div>";
		}

		// if the item has children and we're allowed to output tree navigation (maxDepth)
		// then call this same function again for the item's children
		if($item->hasChildren() && $maxDepth) {
			if($class == 'nav') $class = 'nav nav-tree';
			$out .= renderNavTree($item->children, $maxDepth-1, $fieldNames, $class);
		}

		// close the list item
		$out .= "</li>";
	}

	// if output was generated above, wrap it in a <ul>
	if($out) $out = "<ul class='$class'>$out</ul>\n";

	// return the markup we generated above
	return $out;
}

</syntaxhighlight>