next/prev links in header

layouts/cat-nav.erb

@@ -13,7 +13,7 @@
             <%= render 'list-item', :item => i, :episteme => false %>
           <% end %>
           <% if size > num %>
-            <li>...(<%= size - num %> more)...</li>
+            <li>...<%= size - num %> more...</li>
           <% end %>
           <% items.reverse.slice(0, num/2).reverse.each do |i| %>
             <%= render 'list-item', :item => i, :episteme => false %>

layouts/header.erb

@@ -6,6 +6,9 @@
     <link rel="stylesheet" type="text/css" href="/styles/default.css"/>
     <meta name="generator" content="nanoc"/>
     <link rel="alternate" href="/rss.xml" type="application/rss+xml" title="<%= @site.title %>"/>
+
+    <% unless @site.before(@item).nil? %><link rel="prev" href="<%= @site.before(@item).path %>"/><% end %>
+    <% unless @site.after(@item).nil? %><link rel="next" href="<%= @site.after(@item).path %>"/><% end %>
     <!-- google analytics -->
     <script type="text/javascript">
       var _gaq = _gaq || [];

lib/default.rb

@@ -145,6 +145,26 @@ class Nanoc::Site
   def latest_category? cat
     latest_article.category == cat unless latest_article.nil?
   end
+
+  def before item
+    items = items_by_date
+    index = items.index(item)
+    if index.nil? or index.zero? or not blog?
+      nil
+    else
+      items[index - 1]
+    end
+  end
+
+  def after item
+    items = items_by_date
+    index = items.index(item)
+    if index.nil? or not blog?
+      nil
+    else
+      items[index + 1]
+    end
+  end
 end
 
 def category name_or_cat