Question

Im working on a prototype, and would like to build a multi level navigation – however not by looping through an array. I have a $depth and a $children, which should determine the depth of the navigation and the number of children on each level. So $depth = 4, $children = 8 would yield 4096 menu items.

This is a snippet af the output I would like:

<ul>
    <li class="level-1">
        <a href="#">Subject 1</a>
        <ul>
            <li class="level-2">
                <a href="#">Subject 1.1</a>
                <ul>
                    <li class="level-3">
                        <a href="#">Subject 1.1.1</a>
                    </li>
                    ...
                </ul>
            </li>
            ...
        </ul>
    </li>
    ...
</ul>

So far I have tried this, but I cant get my head around it 🙁

function draw_list ($depth, $children) {

  echo '<ul>';

  for ($i = 0; $i < $children; $i++) {

    echo '<li>' . ($i++);

    $depth--;

    if ($depth > 0) {

      echo draw_list($depth, $children);

    }

    echo '</li>';

  }

  echo '</ul>';


}

Answer 1

Several things required as I see it…

• The $depth--; needs to be outside of the for loop
• You were incrementing $i twice, once in the for statement, and then again on the echo '<li>' . ($i++);
• The $depth check was stopping one early, so make >= instead of just > (Edit, thinking about it, this is an incorrect statement)

That should give you…

function draw_list ($depth, $children) {  
  echo '<ul>';
  $depth--;
  for ($i = 0; $i < $children; $i++) {
    echo '<li>' . $i;
    if ($depth > 0) {
      echo draw_list($depth, $children);
    }
    echo '</li>';
  }
  echo '</ul>';
}

Update

For the display of the level numbering, try passing a string value through as a parameter…

function draw_list ($depth, $children, $display=''){  
  echo '<ul>';
  $depth--;
  for ($i = 0; $i < $children; $i++) {
    echo '<li>' . $display . ($i + 1);
    if ($depth > 0) {
      echo draw_list($depth, $children, $display . ($i + 1) . '.');
    }
    echo '</li>';
  }
  echo '</ul>';
}