lib/nanoc/helpers/link_to.rb in nanoc-2.1.6 vs lib/nanoc/helpers/link_to.rb in nanoc-2.2

@@ -5,10 +5,11 @@
   # To activate this helper, +include+ it, like this:
   #
   #   include Nanoc::Helpers::LinkTo
   module LinkTo
 
+    require 'nanoc/helpers/html_escape'
     include Nanoc::Helpers::HTMLEscape
 
     # Creates a HTML link to the given path or page/asset representation, and
     # with the given text.
     #
@@ -64,9 +65,48 @@
         # Create message
         "<span class=\"active\" title=\"You're here.\">#{text}</span>"
       else
         link_to(text, path_or_rep, attributes)
       end
+    end
+
+    # Returns the relative path from the current page to the given path or
+    # page/asset representation.
+    #
+    # +path_or_rep+:: the URL or path (a String) to where the relative should
+    #                 point, or the page or asset representation to which the
+    #                 relative should point.
+    #
+    # Example:
+    #
+    #   # if the current item's path is /foo/bar/
+    #   relative_path('/foo/qux/')
+    #   # => '../qux/'
+    def relative_path_to(path_or_rep)
+      require 'pathname'
+
+      # Find path
+      path = path_or_rep.is_a?(String) ? path_or_rep : path_or_rep.path
+
+      # Get source and destination paths
+      dst_path   = Pathname.new(path)
+      src_path   = Pathname.new(@item.path)
+
+      # Calculate elative path (method depends on whether destination is a
+      # directory or not).
+      if src_path.to_s[-1,1] != '/'
+        relative_path = dst_path.relative_path_from(src_path.dirname).to_s
+      else
+        relative_path = dst_path.relative_path_from(src_path).to_s
+      end
+
+      # Add trailing slash if necessary
+      if dst_path.to_s[-1,1] == '/'
+        relative_path += '/'
+      end
+
+      # Done
+      relative_path
     end
 
   end
 
 end