Mon Jan  4 06:32:27 UTC 2010  pix@kepibu.org
  * :empty selector
diff -rN -u old-Oh, Ducks!/notes new-Oh, Ducks!/notes
--- old-Oh, Ducks!/notes	2015-11-15 14:59:00.000000000 +0000
+++ new-Oh, Ducks!/notes	2015-11-15 14:59:00.000000000 +0000
@@ -134,7 +134,7 @@
  * [ ] selectors involving descendants
 ** write documentation
 ** improve selector support
-*** positional selectors [18/19]
+*** positional selectors [19/19]
  * [X] :nth-child(an+b)
  * [X] :nth-child(b)
  * [X] :nth-child(odd|even)
@@ -153,7 +153,7 @@
  * [X] :last-of-type
  * [X] :only-child
  * [X] :only-of-type
- * [ ] :empty
+ * [X] :empty
 *** attribute selectors [0/7]
  * [ ] attribute-present  [att]
  * [ ] attribute-equal    [att=val]
diff -rN -u old-Oh, Ducks!/selectors.lisp new-Oh, Ducks!/selectors.lisp
--- old-Oh, Ducks!/selectors.lisp	2015-11-15 14:59:00.000000000 +0000
+++ new-Oh, Ducks!/selectors.lisp	2015-11-15 14:59:00.000000000 +0000
@@ -40,6 +40,7 @@
 (defclass nth-last-child-selector (nth-child-selector) ())
 (defclass nth-of-type-selector (nth-child-selector) ())
 (defclass nth-last-of-type-selector (nth-of-type-selector) ())
+(defclass empty-selector (simple-selector) ())
 
 (defmethod initialize-instance :after ((selector nth-child-selector)
                                        &key (asign "+") a
@@ -182,6 +183,8 @@
       (list* (make-instance 'nth-of-type-selector      :a 0 :b 1)
              (make-instance 'nth-last-of-type-selector :a 0 :b 1)
              (parse-selector &rest)))
+    (#T(regexp$ (":empty")       ())
+      (cons (make-instance 'empty-selector)           (parse-selector &rest)))
     (#T(regexp$ (#\# $name)      (?id))
      (cons (make-instance 'id-selector :arg id)       (parse-selector &rest)))
     (#T(regexp$ (#\. $name)      (?class))
@@ -246,6 +249,9 @@
             (remove-if-not (rcurry #'element-type-equal (element-type element))
                            (element-children parent))))))
 
+(defmethod subject-p ((selector empty-selector) element)
+  (= 0 (length (element-children element))))
+
 (defmethod subject-p ((selector class-selector) element)
   (member (selector-arg selector)
           (element-classes element)
diff -rN -u old-Oh, Ducks!/tests.lisp new-Oh, Ducks!/tests.lisp
--- old-Oh, Ducks!/tests.lisp	2015-11-15 14:59:00.000000000 +0000
+++ new-Oh, Ducks!/tests.lisp	2015-11-15 14:59:00.000000000 +0000
@@ -87,6 +87,11 @@
         "<div>I <i>really</i> <b>like</b> cheese.  Do you not <i>dislike</i> cheese?</div>")
   (values i))
 
+(match (#T(html (:model pt)
+		("body :empty" . ?empty))
+	"<div><p><br></p><p>testing<i>i</i>testing</p></div>")
+  (values empty))
+
 ;; Sometimes, you want to match a thing inside a thing, in which case
 ;; combinators should implicitly assume an unspecified right side means
 ;; "whatever element I gave you".