diff --git a/src/parser/aast/api/AASTNode.php b/src/parser/aast/api/AASTNode.php
index 9fa7890..31def42 100644
--- a/src/parser/aast/api/AASTNode.php
+++ b/src/parser/aast/api/AASTNode.php
@@ -1,262 +1,267 @@
 <?php
 
 /**
  * @group aast
  */
 abstract class AASTNode {
 
   protected $id;
   protected $l;
   protected $r;
   protected $typeID;
   protected $tree;
 
   // These are public only as a microoptimization to make tree construction
   // faster; do not access them directly.
   public $children = array();
   public $parentNode;
 
   abstract public function isStaticScalar();
   abstract public function getDocblockToken();
   abstract public function evalStatic();
   abstract public function getStringLiteralValue();
 
   public function __construct($id, array $data, AASTTree $tree) {
     $this->id = $id;
     $this->typeID = $data[0];
     if (isset($data[1])) {
       $this->l = $data[1];
     } else {
       $this->l = -1;
     }
     if (isset($data[2])) {
       $this->r = $data[2];
     } else {
       $this->r = -1;
     }
     $this->tree = $tree;
   }
 
   public function getParentNode() {
     return $this->parentNode;
   }
 
   public function getID() {
     return $this->id;
   }
 
   public function getTypeID() {
     return $this->typeID;
   }
 
   public function getTypeName() {
     if (empty($this->typeName)) {
       $this->typeName =
         $this->tree->getNodeTypeNameFromTypeID($this->getTypeID());
     }
     return $this->typeName;
   }
 
   public function getChildren() {
     return $this->children;
   }
 
   public function getChildOfType($index, $type) {
     $child = $this->getChildByIndex($index);
     if ($child->getTypeName() != $type) {
       throw new Exception(
         "Child in position '{$index}' is not of type '{$type}': ".
         $this->getDescription());
     }
 
     return $child;
   }
 
   public function getChildByIndex($index) {
     // NOTE: Microoptimization to avoid calls like array_values() or idx().
 
     $idx = 0;
     foreach ($this->children as $child) {
       if ($idx == $index) {
         return $child;
       }
       ++$idx;
     }
 
     throw new Exception("No child with index '{$index}'.");
   }
 
   /**
    * Build a cache to improve the performance of selectDescendantsOfType(). This
    * cache makes a time/memory tradeoff by aggressively caching node
    * descendants. It may improve the tree's query performance substantially if
    * you make a large number of queries, but also requires a significant amount
    * of memory.
    *
    * This builds a cache for the entire tree and improves performance of all
    * selectDescendantsOfType() calls.
    */
   public function buildSelectCache() {
     $cache = array();
     foreach ($this->getChildren() as $id => $child) {
       $type_id = $child->getTypeID();
       if (empty($cache[$type_id])) {
         $cache[$type_id] = array();
       }
       $cache[$type_id][$id] = $child;
       foreach ($child->buildSelectCache() as $type_id => $nodes) {
         if (empty($cache[$type_id])) {
           $cache[$type_id] = array();
         }
         $cache[$type_id] += $nodes;
       }
     }
     $this->selectCache = $cache;
     return $this->selectCache;
   }
 
   /**
    * Build a cache to improve the performance of selectTokensOfType(). This
    * cache makes a time/memory tradeoff by aggressively caching token types.
    * It may improve the tree's query performance substantially if you make a
    * large enumber of queries, but also requires a signficant amount of memory.
    *
    * This builds a cache for this node only.
    */
   public function buildTokenCache() {
     $cache = array();
     foreach ($this->getTokens() as $id => $token) {
       $cache[$token->getTypeName()][$id] = $token;
     }
     $this->tokenCache = $cache;
     return $this->tokenCache;
   }
 
 
   /**
    * Select all tokens of a given type.
    */
   public function selectTokensOfType($type_name) {
     if (isset($this->tokenCache)) {
       return idx($this->tokenCache, $type_name, array());
     } else {
       $result = array();
       foreach ($this->getTokens() as $id => $token) {
         if ($token->getTypeName() == $type_name) {
           $result[$id] = $token;
         }
       }
       return $result;
     }
   }
 
   public function selectDescendantsOfType($type_name) {
-    $type = $this->getTypeIDFromTypeName($type_name);
+    return $this->selectDescendantsOfTypes(array($type_name));
+  }
+
+  public function selectDescendantsOfTypes(array $type_names) {
+    $nodes = array();
+    foreach ($type_names as $type_name) {
+      $type = $this->getTypeIDFromTypeName($type_name);
 
-    if (isset($this->selectCache)) {
-      if (isset($this->selectCache[$type])) {
-        $nodes = $this->selectCache[$type];
+      if (isset($this->selectCache)) {
+        if (isset($this->selectCache[$type])) {
+          $nodes = $nodes + $this->selectCache[$type];
+        }
       } else {
-        $nodes = array();
+        $nodes = $nodes + $this->executeSelectDescendantsOfType($this, $type);
       }
-    } else {
-      $nodes = $this->executeSelectDescendantsOfType($this, $type);
     }
 
     return AASTNodeList::newFromTreeAndNodes($this->tree, $nodes);
   }
 
   protected function executeSelectDescendantsOfType($node, $type) {
     $results = array();
     foreach ($node->getChildren() as $id => $child) {
       if ($child->getTypeID() == $type) {
         $results[$id] = $child;
       }
       $results += $this->executeSelectDescendantsOfType($child, $type);
     }
     return $results;
   }
 
   public function getTokens() {
     if ($this->l == -1 || $this->r == -1) {
       return array();
     }
     $tokens = $this->tree->getRawTokenStream();
     $result = array();
     foreach (range($this->l, $this->r) as $token_id) {
       $result[$token_id] = $tokens[$token_id];
     }
     return $result;
   }
 
   public function getConcreteString() {
     $values = array();
     foreach ($this->getTokens() as $token) {
       $values[] = $token->getValue();
     }
     return implode('', $values);
   }
 
   public function getSemanticString() {
     $tokens = $this->getTokens();
     foreach ($tokens as $id => $token) {
       if ($token->isComment()) {
         unset($tokens[$id]);
       }
     }
     return implode('', mpull($tokens, 'getValue'));
   }
 
   public function getDescription() {
     $concrete = $this->getConcreteString();
     if (strlen($concrete) > 75) {
       $concrete = substr($concrete, 0, 36).'...'.substr($concrete, -36);
     }
 
     $concrete = addcslashes($concrete, "\\\n\"");
 
     return 'a node of type '.$this->getTypeName().': "'.$concrete.'"';
   }
 
   protected function getTypeIDFromTypeName($type_name) {
     return $this->tree->getNodeTypeIDFromTypeName($type_name);
   }
 
   public function getOffset() {
     $stream = $this->tree->getRawTokenStream();
     if (empty($stream[$this->l])) {
       return null;
     }
     return $stream[$this->l]->getOffset();
   }
 
   public function getSurroundingNonsemanticTokens() {
     $before = array();
     $after  = array();
 
     $tokens = $this->tree->getRawTokenStream();
 
     if ($this->l != -1) {
       $before = $tokens[$this->l]->getNonsemanticTokensBefore();
     }
 
     if ($this->r != -1) {
       $after = $tokens[$this->r]->getNonsemanticTokensAfter();
     }
 
     return array($before, $after);
   }
 
   public function getLineNumber() {
     return idx($this->tree->getOffsetToLineNumberMap(), $this->getOffset());
   }
 
   public function dispose() {
     foreach ($this->getChildren() as $child) {
       $child->dispose();
     }
 
     unset($this->selectCache);
   }
 
 }