module InheritedResources::PolymorphicHelpers

def parent


variable name: @task, @file, @note...
Returns the parent object. They are also available with the instance 
def parent
  if parent_type
    p = instance_variable_get("@#{parent_type}")
    p || instance_variable_set("@#{parent_type}", association_chain[-1])
  end
end

def parent?


If the polymorphic association is optional, we might not have a parent. 
def parent?
  if resources_configuration[:polymorphic][:optional]
    parents_symbols.size > 1 || !parent_type.nil?
  else
    true
  end
end

def parent_class 

def parent_class
  parent.class if parent_type
end

def parent_type


as parent types.
Returns the parent type. A Comments class can have :task, :file, :note 
def parent_type
  unless @parent_type
    symbols_for_association_chain
  end
  @parent_type
end

def symbols_for_association_chain #:nodoc:

:nodoc:

params are missing.
When optional is given, it does not raise errors if the polymorphic

params keys to see which polymorphic parent matches the given params.
If the parents_symbols find :polymorphic, it goes through the

Maps parents_symbols to build association chain. 
def symbols_for_association_chain #:nodoc:
  polymorphic_config = resources_configuration[:polymorphic]
  parents_symbols.map do |symbol|
    if symbol == :polymorphic
      params_keys = params.keys
      keys = polymorphic_config[:symbols].map do |poly|
        params_keys.include?(resources_configuration[poly][:param].to_s) ? poly : nil
      end.compact
      if keys.empty?
        raise ScriptError, "Could not find param for polymorphic association. The request " <<
                           "parameters are #{params.keys.inspect} and the polymorphic " <<
                           "associations are #{polymorphic_config[:symbols].inspect}." unless polymorphic_config[:optional]
        nil
      else
        @parent_type = keys[-1].to_sym
	@parent_types = keys.map(&:to_sym)
      end
    else
      symbol
    end
  end.flatten.compact
end