class ActiveModel::Name

def _singularize(string) 

def _singularize(string)
  ActiveSupport::Inflector.underscore(string).tr("/".freeze, "_".freeze)
end

def human(options = {})

Specify +options+ with additional translating options.

BlogPost.model_name.human # => "Blog post"

end
extend ActiveModel::Naming
class BlogPost

it will underscore then humanize the class name.
Transform the model name into a more human format, using I18n. By default, 
def human(options = {})
  return @human unless @klass.respond_to?(:lookup_ancestors) &&
                       @klass.respond_to?(:i18n_scope)
  defaults = @klass.lookup_ancestors.map do |klass|
    klass.model_name.i18n_key
  end
  defaults << options[:default] if options[:default]
  defaults << @human
  options = { scope: [@klass.i18n_scope, :models], count: 1, default: defaults }.merge!(options.except(:default))
  I18n.translate(defaults.shift, options)
end

def initialize(klass, namespace = nil, name = nil)

# => "Foo::Bar"
ActiveModel::Name.new(Foo::Bar).to_s

end
end
class Bar
module Foo

respectively.
and +name+ option will take the namespace and name of the given class
Returns a new ActiveModel::Name instance. By default, the +namespace+ 
def initialize(klass, namespace = nil, name = nil)
  @name = name || klass.name
  raise ArgumentError, "Class name cannot be blank. You need to supply a name argument when anonymous class given" if @name.blank?
  @unnamespaced = @name.sub(/^#{namespace.name}::/, "") if namespace
  @klass        = klass
  @singular     = _singularize(@name)
  @plural       = ActiveSupport::Inflector.pluralize(@singular)
  @element      = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(@name))
  @human        = ActiveSupport::Inflector.humanize(@element)
  @collection   = ActiveSupport::Inflector.tableize(@name)
  @param_key    = (namespace ? _singularize(@unnamespaced) : @singular)
  @i18n_key     = @name.underscore.to_sym
  @route_key          = (namespace ? ActiveSupport::Inflector.pluralize(@param_key) : @plural.dup)
  @singular_route_key = ActiveSupport::Inflector.singularize(@route_key)
  @route_key << "_index" if @plural == @singular
end