Recipes¶

use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

// Site pages as an adjacency list, e.g. SELECT id, parent_id, title, url FROM page ORDER BY position
$pages = [
    ['id' => 1, 'parent_id' => null, 'title' => 'Home',        'url' => '/'],
    ['id' => 2, 'parent_id' => null, 'title' => 'Products',    'url' => '/products'],
    ['id' => 3, 'parent_id' => 2,    'title' => 'Laptops',     'url' => '/products/laptops'],
    ['id' => 4, 'parent_id' => 3,    'title' => 'Ultrabooks',  'url' => '/products/laptops/ultrabooks'],
    ['id' => 5, 'parent_id' => 3,    'title' => 'Gaming',      'url' => '/products/laptops/gaming'],
    ['id' => 6, 'parent_id' => 2,    'title' => 'Phones',      'url' => '/products/phones'],
    ['id' => 7, 'parent_id' => 6,    'title' => 'Android',     'url' => '/products/phones/android'],
    ['id' => 8, 'parent_id' => null, 'title' => 'Support',     'url' => '/support'],
    ['id' => 9, 'parent_id' => 8,    'title' => 'Returns',     'url' => '/support/returns'],
];
$currentUrl = '/products/laptops';

$menu = Tree::fromAdjacencyList($pages)
    ->activeTrail(fn(array $page) => $page['url'] === $currentUrl)
    ->map(fn(array $page) => $page + ['active' => $page['url'] === $currentUrl])
    ->toNestedArray();

// Render as HTML. The menu is small, so a recursive closure is fine here.
$render = function (array $items, int $indent = 0) use (&$render): string {
    $pad = str_repeat('  ', $indent);
    $html = "{$pad}<ul>\n";
    foreach ($items as $item) {
        $class = $item['active'] ? ' class="active"' : '';
        $html .= "{$pad}  <li{$class}><a href=\"{$item['url']}\">{$item['title']}</a>";
        $html .= $item['children'] === [] ? '' : "\n" . $render($item['children'], $indent + 2) . "{$pad}  ";
        $html .= "</li>\n";
    }

    return $html . "{$pad}</ul>\n";
};

echo $render($menu);

use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';

// The trail without siblings, and nothing below the current page.
$crumbs = Tree::fromNestedSet($rows)
    ->activeTrail(fn(array $c) => $c['slug'] === 'cases', siblings: false, activeChildrenDepth: 0, multiple: false)
    ->map(fn(array $c) => $c['title'])
    ->iterate();

echo implode(' › ', iterator_to_array($crumbs, false)), "\n";

use Ghispi\TreeTransform\Strategy\KeepAncestors;
use Ghispi\TreeTransform\Strategy\OnMatch;
use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';
$printTree = require __DIR__ . '/support/print-tree.php';

$query = 'sh';
$matches = fn(array $c) => mb_stripos($c['title'], $query) !== false;
$label = fn(array $c) => $matches($c) ? "[{$c['title']}]" : $c['title'];

// Matches with their path to the root, so the user sees where each hit lives.
echo "Search \"{$query}\":\n";
echo $printTree(Tree::fromNestedSet($rows)->filter($matches, new KeepAncestors()), $label);

// KeepDescendants also shows everything inside a matching category, without testing it.
echo "\nSearch \"phones\", with the contents of matches:\n";
echo $printTree(
    Tree::fromNestedSet($rows)->filter(
        fn(array $c) => mb_stripos($c['title'], 'phones') !== false,
        new KeepAncestors(OnMatch::KeepDescendants),
    ),
    fn(array $c) => $c['title'],
);

use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';
$selectedId = 9;

// iterate() streams depth => node, so the options are written without building a tree in memory.
echo "<select name=\"category\">\n";
foreach (Tree::fromNestedSet($rows)->depthWindow(1)->iterate() as $depth => $category) {
    printf(
        "  <option value=\"%d\"%s>%s%s</option>\n",
        $category['id'],
        $category['id'] === $selectedId ? ' selected' : '',
        str_repeat('&nbsp;&nbsp;', $depth),
        htmlspecialchars($category['title']),
    );
}
echo "</select>\n";

use Ghispi\TreeTransform\Strategy\KeepAncestors;
use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';
$printTree = require __DIR__ . '/support/print-tree.php';

// Keep a category if it has products itself, or if any category below it does.
// KeepAncestors keeps the path to every category with products; empty branches disappear.
$nonEmpty = Tree::fromNestedSet($rows)
    ->filter(fn(array $c) => $c['products'] > 0, new KeepAncestors());

echo $printTree($nonEmpty, fn(array $c) => $c['title'] . ($c['products'] > 0 ? " ({$c['products']})" : ''));

use Ghispi\TreeTransform\Strategy\MinMatches;
use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';
$printTree = require __DIR__ . '/support/print-tree.php';

// Show a category only if at least two categories in its subtree (itself included) have products.
echo $printTree(
    Tree::fromNestedSet($rows)->filter(fn(array $c) => $c['products'] > 0, new MinMatches(2)),
    fn(array $c) => $c['title'],
);

use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';
$printTree = require __DIR__ . '/support/print-tree.php';

// A top navigation bar without the "Shop" root: levels 1 and 2 only.
echo "Top navigation:\n";
echo $printTree(Tree::fromNestedSet($rows)->depthWindow(1, 2), fn(array $c) => $c['title']);

// A sidebar for one section: select the branch (here with a filter on the root path), then drop the levels above.
// With a database, select the branch with WHERE lft >= ? AND rgt <= ? instead: the source reads any subset.
$section = 'Electronics';
$sidebar = Tree::fromNestedSet($rows)
    ->filter(fn(array $c, int $depth) => $depth !== 1 || $c['title'] === $section)
    ->depthWindow(2);

echo "\nSidebar for {$section}:\n";
echo $printTree($sidebar, fn(array $c) => $c['title']);

use Ghispi\TreeTransform\Strategy\Promote;
use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';
$printTree = require __DIR__ . '/support/print-tree.php';

// Only categories with products. Empty intermediate levels are removed and their matching
// descendants move up, so a category list has no dead ends.
$flat = Tree::fromNestedSet($rows)
    ->filter(fn(array $c) => $c['products'] > 0, new Promote());

echo $printTree($flat, fn(array $c) => "{$c['title']} ({$c['products']})");

use Ghispi\TreeTransform\Strategy\MatchState;
use Ghispi\TreeTransform\Tree;

require __DIR__ . '/../vendor/autoload.php';

$rows = require __DIR__ . '/support/shop.php';

// Show the whole tree, but highlight hits, open their ancestors and grey out the rest.
$query = 'es';
$items = Tree::fromNestedSet($rows)
    ->annotate(
        fn(array $c) => str_contains(strtolower($c['title']), $query),
        fn(array $c, MatchState $state) => [
            'title' => $c['title'],
            'class' => match ($state) {
                MatchState::Match => 'hit',
                MatchState::AncestorOfMatch => 'open',
                MatchState::DescendantOfMatch => 'inside-hit',
                MatchState::None => 'dimmed',
            },
        ],
    )
    ->iterate();

foreach ($items as $depth => $item) {
    printf("%s<li class=\"%s\">%s</li>\n", str_repeat('  ', $depth), $item['class'], $item['title']);
}