Add render_or_call_method_or_proc method.

I'd love to find a better name for it.

lib/active_admin/view_helpers/method_or_proc_helper.rb

@@ -23,4 +23,16 @@ def call_method_or_proc_on(obj, symbol_or_proc, options = {})
     end
   end
 
+  # Many configuration options (Ex: site_title, title_image) could either be
+  # static (String), methods (Symbol) or procs (Proc). This helper takes care of
+  # returning the content when String or call call_method_or_proc_on when Symbol or Proc.
+  #
+  def render_or_call_method_or_proc_on(obj, string_symbol_or_proc, options = {})
+    case string_symbol_or_proc
+    when Symbol, Proc
+      call_method_or_proc_on(obj, string_symbol_or_proc, options)
+    when String
+      string_symbol_or_proc
+    end
+  end
 end

spec/unit/renderer_spec.rb

@@ -105,4 +105,22 @@ def to_html
       renderer.send(:call_method_or_proc_on, obj, p).should == obj.size
     end
   end
+
+  describe "#render_or_call_method_or_proc_on" do
+    let(:renderer){ Renderer.new(action_view) }
+    let(:obj){ "Hello World" }
+    it "should return nil if no symbol or proc given" do
+      renderer.send(:render_or_call_method_or_proc_on, obj, 1).should == nil
+    end
+    it "should return the string if a string is given" do
+      renderer.send(:render_or_call_method_or_proc_on, obj, "Hello!").should == "Hello!"
+    end
+    it "should call the method if a symbol is given" do
+      renderer.send(:render_or_call_method_or_proc_on, obj, :size).should == obj.size
+    end
+    it "should call the proc with the object if a proc is given" do
+      p = Proc.new{|string| string.size }
+      renderer.send(:render_or_call_method_or_proc_on, obj, p).should == obj.size
+    end
+  end
 end