issue-38: Support ArrayAccess objects in pluck

test/CollectionsTest.php

@@ -1,5 +1,7 @@
 <?php
 
+include_once 'CustomArray.php';
+
 class UnderscoreCollectionsTest extends PHPUnit_Framework_TestCase {
 
   public function testEach() {
@@ -314,6 +316,14 @@ public function testPluck() {
     $this->assertEquals(array(40, 50, 60), __::pluck($stooges, 'age'));
     $this->assertEquals(array('bar'), __::pluck($stooges, 'foo'));
     $this->assertEquals(array('bar'), __($stooges)->pluck('foo'), 'works with OO-style call');
+
+    // extra: ArrayAccess
+    $persons = array(
+      self::createPerson('moe', 40),
+      self::createPerson('larry', 50),
+      self::createPerson('curly', 60)
+    );
+    $this->assertEquals(array('moe', 'larry', 'curly'), __::pluck($persons, 'name'), 'pulls names out of ArrayAccess objects');
 
     // docs
     $stooges = array(
@@ -324,6 +334,14 @@ public function testPluck() {
     $this->assertEquals(array('moe', 'larry', 'curly'), __::pluck($stooges, 'name'));
   }
 
+  private static function createPerson($name, $age) {
+    $person = new CustomArray();
+    $person['name'] = $name;
+    $person['age'] = $age;
+
+    return $person;
+  }
+
   public function testMax() {
     // from js
     $this->assertEquals(3, __::max(array(1,2,3)), 'can perform a regular max');

test/CustomArray.php

@@ -0,0 +1,23 @@
+<?php
+
+class CustomArray implements ArrayAccess {
+
+  private $_data;
+
+  public function offsetExists($offset) {
+    return array_key_exists($offset, $this->_data);
+  }
+
+  public function offsetGet($offset) {
+    return $this->_data[$offset];
+  }
+
+  public function offsetSet($offset, $value) {
+    $this->_data[$offset] = $value;
+  }
+
+  public function offsetUnset($offset) {
+    unset($this->_data[$offset]);
+  }
+
+}

underscore.php

@@ -112,8 +112,16 @@ public function pluck($collection=null, $key=null) {
 
     $return = array();
     foreach($collection as $item) {
+      $found = false;
       foreach($item as $k=>$v) {
         if($k === $key) $return[] = $v;
+        $found = true;
+      }
+
+      // Classes implementing ArrayAccess don't fully work like normal arrays. It's not possible to get the list of set
+      // keys and values by iterating over an object of such class. isset works though.
+      if (!$found && $item instanceof ArrayAccess && isset($item[$key])) {
+        $return[] = $item[$key];
       }
     }
     return self::_wrap($return);