Enable passing a symbol to :meta to signal a method to call.

lib/paper_trail/has_paper_trail.rb

@@ -117,7 +117,14 @@ module PaperTrail
       def merge_metadata(data)
         # First we merge the model-level metadata in `meta`.
         meta.each do |k,v|
-          data[k] = v.respond_to?(:call) ? v.call(self) : v
+          data[k] = 
+            if v.respond_to?(:call)
+              v.call(self)
+            elsif v.is_a?(Symbol) && respond_to?(v)
+              send(v)
+            else
+              v
+            end
         end
         # Second we merge any extra data from the controller (if available).
         data.merge(PaperTrail.controller_info || {})

test/paper_trail_model_test.rb

@@ -21,8 +21,13 @@ end
 class Article < ActiveRecord::Base
   has_paper_trail :ignore => [:title],
                   :meta   => {:answer => 42,
+                              :action => :action_data_provider_method,
                               :question => Proc.new { "31 + 11 = #{31 + 11}" },
                               :article_id => Proc.new { |article| article.id } }
+
+  def action_data_provider_method
+    self.object_id.to_s
+  end
 end
 
 class Book < ActiveRecord::Base
@@ -528,6 +533,10 @@ class HasPaperTrailModelTest < Test::Unit::TestCase
         assert_equal @article.id, @article.versions.last.article_id
       end
 
+      should 'store dynamic meta data based on a method of the item' do
+        assert_equal @article.action_data_provider_method, @article.versions.last.action
+      end
+
 
       context 'and updated' do
         setup { @article.update_attributes! :content => 'Better text.' }

test/schema.rb

@@ -25,6 +25,7 @@ ActiveRecord::Schema.define(:version => 0) do
 
     # Metadata columns.
     t.integer :answer
+    t.string :action
     t.string  :question
     t.integer :article_id