class ActionView::Renderer

each time render is called.
the setup and logic necessary to render a view and a new object is created
TemplateRenderer and PartialRenderer objects are wrappers which do all
method and render a partial or a template based on the options. The
The Renderer will parse the options from the render or render_body
actually renders the template.
to other objects like TemplateRenderer and PartialRenderer which
This is the main entry point for rendering. It basically delegates
= Action View Renderer

def cache_hits # :nodoc:

:nodoc: 
def cache_hits # :nodoc:
  @cache_hits ||= {}
end

def collection_from_object(object) 

def collection_from_object(object)
  object if object.respond_to?(:to_ary)
end

def collection_from_options(options) 

def collection_from_options(options)
  if options.key?(:collection)
    collection = options[:collection]
    collection || []
  end
end

def initialize(lookup_context) 

def initialize(lookup_context)
  @lookup_context = lookup_context
end

def render(context, options)

Main render entry point shared by Action View and Action Controller. 
def render(context, options)
  render_to_object(context, options).body
end

def render_body(context, options)

so in such cases, we just wrap them in an array.
Note that partials are not supported to be rendered with streaming,

a streaming body that renders the template piece by piece.
Render but returns a valid Rack body. If fibers are defined, we return 
def render_body(context, options)
  if options.key?(:partial)
    [render_partial(context, options)]
  else
    StreamingTemplateRenderer.new(@lookup_context).render(context, options)
  end
end

def render_partial(context, options, &block) # :nodoc:

:nodoc:
Direct access to partial rendering. 
def render_partial(context, options, &block) # :nodoc:
  render_partial_to_object(context, options, &block).body
end

def render_partial_to_object(context, options, &block) # :nodoc:

:nodoc: 
def render_partial_to_object(context, options, &block) # :nodoc:
  partial = options[:partial]
  if String === partial
    collection = collection_from_options(options)
    if collection
      # Collection + Partial
      renderer = CollectionRenderer.new(@lookup_context, options)
      renderer.render_collection_with_partial(collection, partial, context, block)
    else
      if options.key?(:object)
        # Object + Partial
        renderer = ObjectRenderer.new(@lookup_context, options)
        renderer.render_object_with_partial(options[:object], partial, context, block)
      else
        # Partial
        renderer = PartialRenderer.new(@lookup_context, options)
        renderer.render(partial, context, block)
      end
    end
  else
    collection = collection_from_object(partial) || collection_from_options(options)
    if collection
      # Collection + Derived Partial
      renderer = CollectionRenderer.new(@lookup_context, options)
      renderer.render_collection_derive_partial(collection, context, block)
    else
      # Object + Derived Partial
      renderer = ObjectRenderer.new(@lookup_context, options)
      renderer.render_object_derive_partial(partial, context, block)
    end
  end
end

def render_template(context, options) # :nodoc:

:nodoc:
Direct access to template rendering. 
def render_template(context, options) # :nodoc:
  render_template_to_object(context, options).body
end

def render_template_to_object(context, options) # :nodoc:

:nodoc: 
def render_template_to_object(context, options) # :nodoc:
  TemplateRenderer.new(@lookup_context).render(context, options)
end

def render_to_object(context, options) # :nodoc:

:nodoc: 
def render_to_object(context, options) # :nodoc:
  if options.key?(:partial)
    render_partial_to_object(context, options)
  else
    render_template_to_object(context, options)
  end
end