be able to use different decorators for different instance variables, useful for collection vs. singular

lib/decorates_before_rendering.rb

@@ -16,7 +16,13 @@ require 'active_support/core_ext/class/attribute'
 module DecoratesBeforeRendering
   module ClassMethods
     def decorates(*unsigiled_ivar_names)
-      self.__ivars_to_decorate__ = unsigiled_ivar_names.map { |i| "@#{i}" }
+      options = {}
+      if unsigiled_ivar_names.last.instance_of?(::Hash)
+        options = unsigiled_ivar_names.pop
+      end
+
+      self.__ivars_to_decorate__ ||= []
+      self.__ivars_to_decorate__ << [ unsigiled_ivar_names.map { |i| "@#{i}" }, options ]
     end
   end
 
@@ -30,16 +36,20 @@ private
   def __decorate_ivars__
     ivars_to_decorate = self.class.__ivars_to_decorate__
 
-    return if ivars_to_decorate.nil?
+    return if ivars_to_decorate.nil? or ivars_to_decorate.empty?
 
-    ivars_to_decorate.each do |ivar_name|
-      ivar = instance_variable_get(ivar_name)
-      instance_variable_set(ivar_name, __decorator_for__(ivar)) unless ivar.nil?
+    ivars_to_decorate.each do |ivar_names, options|
+      ivar_names.each do |ivar_name|
+        if ivar = instance_variable_get(ivar_name)
+          decorator = (options[:with] || __decorator_for__(ivar)).decorate(ivar)
+          instance_variable_set(ivar_name, decorator)
+        end
+      end
     end
   end
 
   def __decorator_for__(ivar)
-    __decorator_name_for__(ivar).constantize.decorate(ivar)
+    __decorator_name_for__(ivar).constantize
   end
 
   def __decorator_name_for__(ivar)

spec/decorates_before_rendering_spec.rb

@@ -1,12 +1,14 @@
 require_relative '../lib/decorates_before_rendering'
 
 class MyCompletelyFakeModelDecorator; end
+class MyOtherCompletelyFakeModelDecorator; end
 
 describe DecoratesBeforeRendering do
   # NOTE: these are married together, so they're tested together.
   describe '::decorates + #render' do
     let(:sentinel) { double(:sentinel) }
     let(:ivar) { double('@ivar') }
+    let(:ivars) { double('@ivars') }
 
     # NOTE: This superclass is here so we know that the correct render gets
     #       called. It can't be defined in the subclass, or else that one
@@ -27,16 +29,17 @@ describe DecoratesBeforeRendering do
       Class.new(superclass) do
         include DecoratesBeforeRendering
 
-        attr_reader :ivar
+        attr_reader :ivar, :ivars
 
-        def initialize(sentinel, ivar)
+        def initialize(sentinel, ivar, ivars = nil)
           super(sentinel)
 
           @ivar = ivar
+          @ivars = ivars
         end
       end
     end
-    let(:instance) { klass.new(sentinel, ivar) }
+    let(:instance) { klass.new(sentinel, ivar, ivars) }
     let(:args) { double('*args') }
 
     context "no ivars" do
@@ -92,5 +95,19 @@ describe DecoratesBeforeRendering do
         subclass_instance.render(args)
       end
     end
+
+    context "Specify a different decorator class for an automatic decorator" do
+      it "should function correctly" do
+        klass.decorates(:ivars, :with => MyOtherCompletelyFakeModelDecorator)
+        klass.decorates(:ivar)
+        subclass_instance = Class.new(klass).new(sentinel, ivar, ivars)
+        sentinel.should_receive(:render).with(args)
+        MyOtherCompletelyFakeModelDecorator.should_receive(:decorate).with(ivars)
+        MyCompletelyFakeModelDecorator.should_receive(:decorate).with(ivar)
+        ivar.stub_chain(:class, :model_name => 'MyCompletelyFakeModel')
+        subclass_instance.render(args)
+      end
+    end
   end
 end
+