KirbyCMS-inspired chainable object class.

chainable-objects.php

<?php
# Chainable objects
# Ex: echo $films->filterBy('rating', 5)->sortBy('release')->flip()->first()->title();
  class obj implements Iterator {
    private $_ = array();
    public function __construct($arr = array()) { $this->_ = is_array($arr[0]) ? array_map(function($a) { return is_object($a) ? $a : new obj($a); }, $arr) : $arr; }
    public function __set($k, $v) { $this->_[$k] = $v; }
    public function __get($k) { return $this->get($this->_, $k); }
    public function __call($k, $args) { return $this->get($this->_, $k, $args[0]); }
    private function get($arr, $k, $date = false) { return isset($arr[$k]) ? (($date AND !is_numeric($arr[$k]) AND strtotime($arr[$k]))?new DateTime($arr[$k]):$arr[$k]) : false; }
    public function rewind() { reset($this->_); }
    public function current() { return current($this->_); }
    public function key() { return key($this->_); }
    public function next() { return next($this->_); }
    public function prev() { return prev($this->_); }
    public function valid() { $key = key($this->_); return ($key !== NULL && $key !== FALSE); }
    public function first() { return array_shift($this->_); }
    public function last() { return array_pop($this->_); }
    public function nth($n) { $arr = array_values($this->_); return (isset($arr[$n-1])) ? $arr[$n-1] : false; }
    public function indexOf($needle) { return array_search($needle, array_values($this->_)); }
    public function count() { return count($this->_); }
    public function toArray() { return $this->_; }
    public function limit($n) { return new obj(array_slice($this->_, 0, $n)); }
    public function slice($o, $n) { return new obj(array_slice($this->_, $o, $n)); }
    public function shuffle() { $keys = array_keys($this->_); shuffle($keys); return new obj(array_replace(array_flip($keys), $this->_)); }
    public function flip() { return new obj(array_reverse($this->_, true)); }
    public function sortBy($k) { 
      $arr = $this->_;
      $values = function($key) use ($arr) { return array_map(create_function('$a', "return (is_object(\$a) AND is_object(\$a->$key(true))) ? \$a->$key(true)->getTimestamp() : strtolower(\$a->$key);"), $arr); };
      if (preg_match('/([a-z]{1}[a-z0-9]*)(?:\s(ASC|DESC))?\s?,\s?([a-z]{1}[a-z0-9]*)(?:\s(ASC|DESC))?/i', $k, $m))
        array_multisort($values($m[1]), (strtolower($m[2])=='desc'?SORT_DESC:SORT_ASC), SORT_REGULAR, $values($m[3]), (strtolower($m[4])=='desc'?SORT_DESC:SORT_ASC), SORT_REGULAR, $arr);
      else array_multisort($values($k), SORT_ASC, SORT_REGULAR, $arr);
      return new obj($arr);
    }
    public function filter($c) { return new obj(array_filter($this->_, create_function('$a', 'extract(array_map(function($v) use ($a) { $k = array_search($v, $a->toArray()); return is_object($a->$k(true))?$a->$k(true):$v; }, $a->toArray())); return '.$c.';'))); }
    public function filterBy($k, $v, $s = false) { return $s ? $this->filter("in_array('$v', array_map('trim', explode('$s', \$$k)))") : $this->filter("\$$k == \"$v\""); }
    public function findBy($k, $v, $s = false) { return $this->filterBy($k, $v, $s)->first(); }
    public function kickBy($k, $v, $s = false) { return $s ? $this->filter("!in_array('$v', array_map('trim', explode('$s', \$$k)))") : $this->filter("\$$k != \"$v\""); }
    public function sum($k) { return array_sum(array_map(function($a) use ($k) { return $a->$k(); }, $this->_)); }
  }

examples.php

<?php
# Sample data
  $films = array(
    array(
      'title'   => 'Cloud Atlas',
      'release' => '2013-3-13',
      'rating'  => 4.5
      ),
    array(
      'title'   => 'Oblivion',
      'release' => '2013-4-10',
      'rating'  => 4.5
      ),
    array(
      'title'   => 'Lawless',
      'release' => '2012-9-12',
      'rating'  => 5
      ),
    array(
      'title'   => 'Iron Man 3',
      'release' => '2013-4-24',
      'rating'  => 3.5
      ),
    array(
      'title'   => 'Django Unchained',
      'release' => '2013-1-16',
      'rating'  => 5
      ),
    array(
      'title'   => 'Looper',
      'release' => '2012-10-31',
      'rating'  => 4
      )
  );
# Examples
  include 'chainable-objects.php';
  $films = new obj($films);
?>

<h1>Full movie list</h1>
<ul>
  <?php foreach ($films->sortBy('release')->flip() as $film): ?>
  <li>
    <em><?php echo $film->title() ?></em>
    released on <time datetime="<?php echo $film->release() ?>"><?php echo $film->release(true)->format('F j, Y') ?></time>
    and rated <strong><?php echo $film->rating() ?></strong>
  </li>
  <?php endforeach ?>
</ul>

<h1>Info</h1>
<ul>
  <li>Number of films: <?php echo $films->count() ?></li>
  <li>Number of 5 rated films: <?php echo $films->filterBy('rating', 5)->count() ?></li>
  <li>Number of < 5 rated films: <?php echo $films->kickBy('rating', 5)->count() ?></li>
  <li>Number of 4+ rated films: <?php echo $films->filter('$rating >= 4')->count() ?></li>
  <li>Random film title: <?php echo $films->shuffle()->first()->title() ?></li>
  <li>Last watched film title: <?php echo $films->sortBy('release')->flip()->first()->title() ?></li>
  <li>Second to last watched film title: <?php echo $films->sortBy('release')->flip()->nth(2)->title() ?></li>
  <li>Last 5-rated watched film title: <?php echo $films->sortBy('rating DESC, release DESC')->first()->title() ?></li>
  <li>First 5-rated watched film title: <?php echo $films->sortBy('release')->findBy('rating', 5)->title() ?></li>
  <li>Number of films released on 2013: <?php echo $films->filter('$release->format("Y") >= 2013')->count() ?></li>
</ul>

<h1>Two last movies I watched</h1>
<ul>
  <?php foreach ($films->sortBy('release')->flip()->limit(2) as $film): ?>
  <li>
    <em><?php echo $film->title() ?></em>
    released on <time datetime="<?php echo $film->release() ?>"><?php echo $film->release(true)->format('F j, Y') ?></time>
    and rated <strong><?php echo $film->rating() ?></strong>
  </li>
  <?php endforeach ?>
</ul>

<h1>Three previous movies I watched</h1>
<ul>
  <?php foreach ($films->sortBy('release')->flip()->slice(2, 3) as $film): ?>
  <li>
    <em><?php echo $film->title() ?></em>
    released on <time datetime="<?php echo $film->release() ?>"><?php echo $film->release(true)->format('F j, Y') ?></time>
    and rated <strong><?php echo $film->rating() ?></strong>
  </li>
  <?php endforeach ?>
</ul>