diff --git a/library/HTMLPurifier/AttrDef.php b/library/HTMLPurifier/AttrDef.php
index cdd90a60..ad7ab384 100644
--- a/library/HTMLPurifier/AttrDef.php
+++ b/library/HTMLPurifier/AttrDef.php
@@ -1,10 +1,12 @@
 <?php
 
+// AttrDef = Attribute Definition
 class HTMLPurifier_AttrDef
 {
-    var $def;
-    function HTMLPurifier_AttrDef($def) {
-        $this->def = $def;
+    function HTMLPurifier_AttrDef() {}
+    
+    function validate() {
+        trigger_error('Cannot call abstract function', E_USER_ERROR);
     }
 }
 
diff --git a/library/HTMLPurifier/AttrDef/Enum.php b/library/HTMLPurifier/AttrDef/Enum.php
new file mode 100644
index 00000000..7cb7ec4c
--- /dev/null
+++ b/library/HTMLPurifier/AttrDef/Enum.php
@@ -0,0 +1,25 @@
+<?php
+
+// Enum = Enumerated
+class HTMLPurifier_AttrDef_Enum extends HTMLPurifier_AttrDef
+{
+    
+    var $valid_values   = array();
+    var $case_sensitive = false; // values according to W3C spec
+    
+    function HTMLPurifier_AttrDef_Enum(
+      $valid_values = array(), $case_sensitive = false) {
+        $this->valid_values = array_flip($valid_values);
+        $this->case_sensitive = $case_sensitive;
+    }
+    
+    function validate($string) {
+        if (!$this->case_sensitive) {
+            $string = ctype_lower($string) ? $string : strtolower($string);
+        }
+        return isset($this->valid_values[$string]);
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/library/HTMLPurifier/Definition.php b/library/HTMLPurifier/Definition.php
index a0e61e2f..8dca40ee 100644
--- a/library/HTMLPurifier/Definition.php
+++ b/library/HTMLPurifier/Definition.php
@@ -92,72 +92,66 @@ class HTMLPurifier_Definition
         $e_form_content = new HTMLPurifier_ChildDef_Optional(''); //unused
         $e_form_button_content = new HTMLPurifier_ChildDef_Optional(''); // unused
         
-        $this->info['ins'] =
-        $this->info['del'] = 
-        $this->info['blockquote'] =
-        $this->info['dd']  =
-        $this->info['li']  =
-        $this->info['div'] = new HTMLPurifier_ElementDef($e_Flow);
+        $this->info['child'] = array();
         
-        $this->info['em']  =
-        $this->info['strong'] =
-        $this->info['dfn']  =
-        $this->info['code'] =
-        $this->info['samp'] =
-        $this->info['kbd']  =
-        $this->info['var']  =
-        $this->info['code'] =
-        $this->info['samp'] =
-        $this->info['kbd']  =
-        $this->info['var']  =
-        $this->info['cite'] =
-        $this->info['abbr'] =
-        $this->info['acronym'] =
-        $this->info['q']    =
-        $this->info['sub']  =
-        $this->info['tt']   =
-        $this->info['sup']  =
-        $this->info['i']    =
-        $this->info['b']    =
-        $this->info['big']  =
-        $this->info['small'] =
-        $this->info['u']    =
-        $this->info['s']    =
-        $this->info['strike'] =
-        $this->info['bdo']  =
-        $this->info['span'] =
-        $this->info['dt']   =
-        $this->info['p']    = 
-        $this->info['h1']   = 
-        $this->info['h2']   = 
-        $this->info['h3']   = 
-        $this->info['h4']   = 
-        $this->info['h5']   = 
-        $this->info['h6']   = new HTMLPurifier_ElementDef($e_Inline);
+        $this->info['child']['ins'] =
+        $this->info['child']['del'] = 
+        $this->info['child']['blockquote'] =
+        $this->info['child']['dd']  =
+        $this->info['child']['li']  =
+        $this->info['child']['div'] = $e_Flow;
         
-        $this->info['ol']   =
-        $this->info['ul']   =
-          new HTMLPurifier_ElementDef(
-            new HTMLPurifier_ChildDef_Required('li')
-          );
+        $this->info['child']['em']  =
+        $this->info['child']['strong'] =
+        $this->info['child']['dfn']  =
+        $this->info['child']['code'] =
+        $this->info['child']['samp'] =
+        $this->info['child']['kbd']  =
+        $this->info['child']['var']  =
+        $this->info['child']['code'] =
+        $this->info['child']['samp'] =
+        $this->info['child']['kbd']  =
+        $this->info['child']['var']  =
+        $this->info['child']['cite'] =
+        $this->info['child']['abbr'] =
+        $this->info['child']['acronym'] =
+        $this->info['child']['q']    =
+        $this->info['child']['sub']  =
+        $this->info['child']['tt']   =
+        $this->info['child']['sup']  =
+        $this->info['child']['i']    =
+        $this->info['child']['b']    =
+        $this->info['child']['big']  =
+        $this->info['child']['small'] =
+        $this->info['child']['u']    =
+        $this->info['child']['s']    =
+        $this->info['child']['strike'] =
+        $this->info['child']['bdo']  =
+        $this->info['child']['span'] =
+        $this->info['child']['dt']   =
+        $this->info['child']['p']    = 
+        $this->info['child']['h1']   = 
+        $this->info['child']['h2']   = 
+        $this->info['child']['h3']   = 
+        $this->info['child']['h4']   = 
+        $this->info['child']['h5']   = 
+        $this->info['child']['h6']   = $e_Inline;
         
-        $this->info['dl']   =
-          new HTMLPurifier_ElementDef(
-            new HTMLPurifier_ChildDef_Required('dt|dd')
-          );
-        $this->info['address'] =
-          new HTMLPurifier_ElementDef(
-            new HTMLPurifier_ChildDef_Optional("#PCDATA | p | $e_inline".
-              " | $e_misc_inline")
-          );
+        $this->info['child']['ol']   =
+        $this->info['child']['ul']   = new HTMLPurifier_ChildDef_Required('li');
         
-        $this->info['img']  =
-        $this->info['br']   =
-        $this->info['hr']   = new HTMLPurifier_ElementDef(new HTMLPurifier_ChildDef_Empty());
+        $this->info['child']['dl']   = new HTMLPurifier_ChildDef_Required('dt|dd');
+        $this->info['child']['address'] =
+          new HTMLPurifier_ChildDef_Optional("#PCDATA | p | $e_inline".
+              " | $e_misc_inline");
         
-        $this->info['pre']  = new HTMLPurifier_ElementDef($e_pre_content);
+        $this->info['child']['img']  =
+        $this->info['child']['br']   =
+        $this->info['child']['hr']   = new HTMLPurifier_ChildDef_Empty();
         
-        $this->info['a']    = new HTMLPurifier_ElementDef($e_a_content);
+        $this->info['child']['pre']  = $e_pre_content;
+        
+        $this->info['child']['a']    = $e_a_content;
         
     }
     
diff --git a/library/HTMLPurifier/Strategy/FixNesting.php b/library/HTMLPurifier/Strategy/FixNesting.php
index b0b2ca0e..ad54ed65 100644
--- a/library/HTMLPurifier/Strategy/FixNesting.php
+++ b/library/HTMLPurifier/Strategy/FixNesting.php
@@ -39,8 +39,8 @@ class HTMLPurifier_Strategy_FixNesting extends HTMLPurifier_Strategy
             // $j is index of end token
             
             // have DTD child def validate children
-            $element_def = $this->definition->info[$tokens[$i]->name];
-            $result = $element_def->child_def->validateChildren($child_tokens);
+            $child_def = $this->definition->info['child'][$tokens[$i]->name];
+            $result = $child_def->validateChildren($child_tokens);
             
             // process result
             if ($result === true) {
diff --git a/library/HTMLPurifier/Strategy/MakeWellFormed.php b/library/HTMLPurifier/Strategy/MakeWellFormed.php
index 3d0e9b67..4e58dd49 100644
--- a/library/HTMLPurifier/Strategy/MakeWellFormed.php
+++ b/library/HTMLPurifier/Strategy/MakeWellFormed.php
@@ -23,10 +23,10 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
                 $result[] = $token;
                 continue;
             }
-            $info = $this->definition->info[$token->name]; // assumption but valid
+            $info = $this->definition->info['child'][$token->name]; // assumption but valid
             
             // test if it claims to be a start tag but is empty
-            if ($info->child_def->type == 'empty' &&
+            if ($info->type == 'empty' &&
                 $token->type == 'start' ) {
                 
                 $result[] = new HTMLPurifier_Token_Empty($token->name,
@@ -35,7 +35,7 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
             }
             
             // test if it claims to be empty but really is a start tag
-            if ($info->child_def->type != 'empty' &&
+            if ($info->type != 'empty' &&
                 $token->type == 'empty' ) {
                 
                 $result[] = new HTMLPurifier_Token_Start($token->name,
diff --git a/library/HTMLPurifier/Strategy/RemoveForeignElements.php b/library/HTMLPurifier/Strategy/RemoveForeignElements.php
index 7418dfc6..e5755bb8 100644
--- a/library/HTMLPurifier/Strategy/RemoveForeignElements.php
+++ b/library/HTMLPurifier/Strategy/RemoveForeignElements.php
@@ -19,7 +19,7 @@ class HTMLPurifier_Strategy_RemoveForeignElements extends HTMLPurifier_Strategy
         $result = array();
         foreach($tokens as $token) {
             if (!empty( $token->is_tag )) {
-                if (!isset($this->definition->info[$token->name])) {
+                if (!isset($this->definition->info['child'][$token->name])) {
                     // invalid tag, generate HTML and insert in
                     $token = new HTMLPurifier_Token_Text(
                         $this->generator->generateFromToken($token)
diff --git a/tests/HTMLPurifier/AttrDef/EnumTest.php b/tests/HTMLPurifier/AttrDef/EnumTest.php
new file mode 100644
index 00000000..8e8acbf7
--- /dev/null
+++ b/tests/HTMLPurifier/AttrDef/EnumTest.php
@@ -0,0 +1,28 @@
+<?php
+
+require_once 'HTMLPurifier/AttrDef/Enum.php';
+
+class HTMLPurifier_AttrDef_EnumTest extends UnitTestCase
+{
+    
+    function testCaseInsensitive() {
+        
+        $def = new HTMLPurifier_AttrDef_Enum(array('one', 'two'));
+        
+        $this->assertTrue($def->validate('one'));
+        $this->assertTrue($def->validate('ONE'));
+        
+    }
+    
+    function testCaseSensitive() {
+        
+        $def = new HTMLPurifier_AttrDef_Enum(array('one', 'two'), true);
+        
+        $this->assertTrue($def->validate('one'));
+        $this->assertFalse($def->validate('ONE'));
+        
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/tests/index.php b/tests/index.php
index 9267a600..5cb61927 100644
--- a/tests/index.php
+++ b/tests/index.php
@@ -32,6 +32,7 @@ $test->addTestFile('HTMLPurifier/Strategy/MakeWellFormedTest.php');
 $test->addTestFile('HTMLPurifier/Strategy/FixNestingTest.php');
 $test->addTestFile('HTMLPurifier/Strategy/CompositeTest.php');
 $test->addTestFile('HTMLPurifier/Strategy/CoreTest.php');
+$test->addTestFile('HTMLPurifier/AttrDef/EnumTest.php');
 
 $test->run( new HtmlReporter() );