Add sizzle to ext/.

Rakefile

@@ -43,7 +43,7 @@ module PrototypeHelper
     }.merge(options)
     
     require_sprockets
-    load_path = [SRC_DIR]
+    load_path = [SRC_DIR, File.join(ROOT_DIR, 'ext', 'sizzle')]
     
     if selector = options[:selector_engine]
       get_selector_engine(selector)
@@ -98,10 +98,11 @@ module PrototypeHelper
   end
   
   def self.get_selector_engine(name)
-    file = File.join(ROOT_DIR, 'vendor', name, 'repository')
-    unless File.exists?(file)
+    submodule = File.join(ROOT_DIR, 'vendor', name, 'repository')
+    ext = File.join(ROOT_DIR, 'ext', name)
+    unless File.exist?(submodule) || File.exist?(ext)
       get_submodule('the required selector engine', "#{name}/repository")
-      unless File.exists?(file)
+      unless File.exist?(submodule)
         puts "The selector engine you required isn't available at vendor/#{name}.\n\n"
         exit
       end

ext/sizzle/selector_engine.js

@@ -0,0 +1,34 @@
+Prototype._original_property = window.Sizzle;
+//= require "repository/sizzle"
+
+Prototype.Selector = (function(engine) {
+  function extend(elements) {
+    for (var i = 0, length = elements.length; i < length; i++) {
+      Element.extend(elements[i]);
+    }
+    return elements;
+  }
+  
+  function select(selector, scope) {
+    return extend(engine(selector, scope || document));
+  }
+
+  function match(element, selector) {
+    return engine.matches(selector, [element]).length == 1;
+  }
+
+  function filter(elements, selector) {
+    return extend(engine.matches(selector, elements));
+  }
+  
+  return {
+    engine:  engine,
+    select:  select,
+    match:   match,
+    filter:  filter
+  };
+})(Sizzle);
+
+// Restore globals.
+window.Sizzle = Prototype._original_property;
+delete Prototype._original_property;