Adding tags to the site payload. Derived mostly from Henrik's implementation in 072d9e7

features/site_data.feature

@@ -49,3 +49,13 @@ Feature: Site data
     When I run jekyll
     Then the _site directory should exist
     And I should see "Awesome Hack" in "_site/index.html"
+
+  Scenario: Use site.tags variable
+    Given I have a _posts directory
+    And I have an "index.html" page that contains "{% for post in site.tags.beer %} {{ post.content }} {% endfor %}"
+    And I have the following posts:
+      | title          | date      | tag  | content            |
+      | Delicious Beer | 3/26/2009 | beer | 1) Yuengling       |
+    When I run jekyll
+    Then the _site directory should exist
+    And I should see "Yuengling" in "_site/index.html"

lib/jekyll/site.rb

@@ -1,8 +1,8 @@
 module Jekyll
 
   class Site
-    attr_accessor :config, :layouts, :posts, :categories, :exclude
-    attr_accessor :source, :dest, :lsi, :pygments, :permalink_style
+    attr_accessor :config, :layouts, :posts, :categories, :exclude,
+                  :source, :dest, :lsi, :pygments, :permalink_style, :tags
 
     # Initialize the site
     #   +config+ is a Hash containing site configurations details
@@ -25,7 +25,8 @@ module Jekyll
     def reset
       self.layouts         = {}
       self.posts           = []
-      self.categories      = Hash.new { |hash, key| hash[key] = Array.new }
+      self.categories      = Hash.new { |hash, key| hash[key] = [] }
+      self.tags            = Hash.new { |hash, key| hash[key] = [] }
     end
 
     def setup
@@ -126,6 +127,7 @@ module Jekyll
           if post.published
             self.posts << post
             post.categories.each { |c| self.categories[c] << post }
+            post.tags.each { |c| self.tags[c] << post }
           end
         end
       end
@@ -137,7 +139,8 @@ module Jekyll
         post.render(self.layouts, site_payload)
       end
 
-      self.categories.values.map { |cats| cats.sort! { |a, b| b <=> a} }
+      self.categories.values.map { |ps| ps.sort! { |a, b| b <=> a} }
+      self.tags.values.map { |ps| ps.sort! { |a, b| b <=> a} }
     rescue Errno::ENOENT => e
       # ignore missing layout dir
     end
@@ -219,7 +222,8 @@ module Jekyll
       {"site" => {
           "time"       => Time.now,
           "posts"      => self.posts.sort { |a,b| b <=> a },
-          "categories" => post_attr_hash('categories')}}
+          "categories" => post_attr_hash('categories'),
+          "tags"       => post_attr_hash('tags')}}
     end
 
     # Filter out any files/directories that are hidden or backup files (start

test/test_site.rb

@@ -9,6 +9,10 @@ class TestSite < Test::Unit::TestCase
       @site = Site.new(Jekyll.configuration)
     end
 
+    should "have an empty tag hash by default" do
+      assert_equal Hash.new, @site.tags
+    end
+
     should "reset data before processing" do
       clear_dest
       @site.process