From 7a606a11d31f855244de2df2993e06f5fb305fbc Mon Sep 17 00:00:00 2001
From: Yorick Peterse <yorickpeterse@gmail.com>
Date: Mon, 3 Nov 2014 22:58:08 +0100
Subject: [PATCH] Parsing support for the :last-child pseudo class.

---
 lib/oga/css/parser.y                                | 13 +++++++++++++
 .../css/parser/pseudo_classes/last_child_spec.rb    | 11 +++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 spec/oga/css/parser/pseudo_classes/last_child_spec.rb

diff --git a/lib/oga/css/parser.y b/lib/oga/css/parser.y
index 1d28d9f..8f6dbd9 100644
--- a/lib/oga/css/parser.y
+++ b/lib/oga/css/parser.y
@@ -501,6 +501,19 @@ end
     )
   end
 
+  ##
+  # Generates the AST for the `:last-child` selector.
+  #
+  # @return [AST::Node]
+  #
+  def on_pseudo_class_last_child
+    return s(
+      :eq,
+      s(:call, 'count', s(:axis, 'following-sibling', s(:test, nil, '*'))),
+      s(:int, 0)
+    )
+  end
+
   private
 
   ##
diff --git a/spec/oga/css/parser/pseudo_classes/last_child_spec.rb b/spec/oga/css/parser/pseudo_classes/last_child_spec.rb
new file mode 100644
index 0000000..ae94ed1
--- /dev/null
+++ b/spec/oga/css/parser/pseudo_classes/last_child_spec.rb
@@ -0,0 +1,11 @@
+require 'spec_helper'
+
+describe Oga::CSS::Parser do
+  context ':last-child pseudo class' do
+    example 'parse the :last-child pseudo class' do
+      parse_css(':last-child').should == parse_xpath(
+        'descendant-or-self::*[count(following-sibling::*) = 0]'
+      )
+    end
+  end
+end