adding support for embedded functions inside the google visualization

lib/google_visualr/base_chart.rb

@@ -4,12 +4,13 @@ class BaseChart
     include GoogleVisualr::Packages
     include GoogleVisualr::ParamHelpers
 
-    attr_accessor :data_table, :listeners
+    attr_accessor :data_table, :listeners, :functions
 
     def initialize(data_table, options={})
       @data_table = data_table
       send(:options=, options)
       @listeners  = []
+      @functions = []
     end
 
     def chart_name
@@ -32,6 +33,10 @@ def add_listener(event, callback)
       @listeners << { :event => event.to_s, :callback => callback }
     end
 
+    def add_function(callback)
+      @functions << { :callback => callback }
+    end
+
     # Generates JavaScript and renders the Google Chart in the final HTML output.
     #
     # Parameters:
@@ -66,6 +71,9 @@ def draw_js(element_id)
         js << "\n    google.visualization.events.addListener(chart, '#{listener[:event]}', #{listener[:callback]});"
       end
       js << "\n    chart.draw(data_table, #{js_parameters(@options)});"
+      @functions.each do |efunction|
+        js << "\n\n #{efunction[:callback]}"
+      end
       js << "\n  };"
       js
     end

spec/google_visualr/base_chart_spec.rb

@@ -43,6 +43,14 @@
       @chart.listeners.should == [{ :event => "select", :callback => "function() {test_event(chart);}" }]
     end
   end
+
+  describe '#add_function' do
+    it 'adds to embedded functions array' do
+      @chart.add_function("function() {alert(\"Nothing to see here\");}")
+      @chart.functions.should == [{ :callback => "function() 
+      {alert(\"Nothing to see here\");}" }]
+    end
+  end
 
   describe "#to_js" do
     it "generates JS" do