PHP return list as a function result

I am an absolute beginner in PHP. I have a file main.php where I have a call to a php function:

<div id="navigation">
        <nav>
            <?php echo navigation('exclude'=>array('/about.php')) ?>
        </nav>
    </div>

I have a file navigation.php which is required in main.php, it has a small constructor to build the right structure of the navigation, it looks like this:

<ul class="navi naviTop">
    <?php foreach($page as $key=>$singlepage){
    
    if(!isset($singlepage['submenu'])){ ?>
    <li class="navIem <?php echo $singlepage['name'];?>">
        <a href="<?php echo $key; ?>">
            <?php echo $singlepage['name'];?>
        </a>
    </li>

    <?php } else { ?>
       <ul class="hasSubs">
           <?php foreach($singlepage['submenu'] as $subkey=>$subpage){ ?>
            <li class="navItem subitem">
                <a href="<?php echo $subkey; ?>">
            <?php echo $subpage['name'];?>
                </a>
            </li>
            <?php } ?>
       </ul>
    <?php } ?>
    <?php } ?>
</ul>

This works completely fine for me, but I want to have some options, that’s why I establish a function:

function navigation($arguments=array()){
    $defaults = array(
        'class' => '',
        'exclude'=> array()
    );
    
    $opts = array_merge($defaults, $arguments);

What is the right way for me to return this HTML structure that I generate by calling the navigation function?

Answer

To keep your code clean, you should seperate the template (html) from the business logic (php). Therefore your approach is great. Here ‘s a short example, how you could solve your issue.

First think about all the data you want to use in your function. As far as we can see, you need the pages and the options. Both arguments are arrays.

function navigation(array $pages = [], array $options = [])
{
    $defaults = [
        'class' => '',
        'exclude' => [],
    ];

    $options = array_merge($defaults, $options);
    include __DIR__ . '/templates/navigation.phtml';
}

As you can see, the function does nothing more, as you have defined already. It takes another array parameter, where the pages are stored in. At the end of the function it includes the navigation template. There ‘s nothing more to do in PHP side.

The template navigation.phtml should look something like you already have.

<ul class="navigation<?php if (!empty($options['class'])):?><?= $options['class'] ?><?php endif; ?>">
    <?php foreach ($pages as $url => $page): ?>
        <?php if (!in_array($url, $options['excludes']): ?>
            <li><a href="<?= $url ?>"><?= $page['name'] ?></a></li>
        <?pgp endif; ?>
    <?php endforeach ?>
</ul>

I ‘ve shortened the code example. To keep the logic in your template as small as possible you could filter the exluded pages before in your function to avoid the in_array if condition in your template.

In your main.php file, you can simple call the navigate function.

<nav>
    <?php navigation($pages, $options) ?>
</nav>

The $pages and $options variables have to be declared before the call of the navigation function.