class ActionDispatch::Routing::RouteSet::NamedRouteCollection

named routes.
maintains an anonymous module that can be used to install helpers for the
A NamedRouteCollection instance is a collection of named routes, and also

def add(name, route) 

def add(name, route)
  key       = name.to_sym
  path_name = :"#{name}_path"
  url_name  = :"#{name}_url"
  if routes.key? key
    @path_helpers_module.undef_method path_name
    @url_helpers_module.undef_method url_name
  end
  routes[key] = route
  helper = UrlHelper.create(route, route.defaults, name)
  define_url_helper @path_helpers_module, path_name, helper, PATH
  define_url_helper @url_helpers_module, url_name, helper, UNKNOWN
  @path_helpers << path_name
  @url_helpers << url_name
end

def add_url_helper(name, defaults, &block)

Used by 'direct', 'resolve', and 'polymorphic' route helpers.
Given a +name+, defines name_path and name_url helpers. 
def add_url_helper(name, defaults, &block)
  helper = CustomUrlHelper.new(name, defaults, &block)
  path_name = :"#{name}_path"
  url_name = :"#{name}_url"
  @path_helpers_module.module_eval do
    redefine_method(path_name) do |*args|
      helper.call(self, args, true)
    end
  end
  @url_helpers_module.module_eval do
    redefine_method(url_name) do |*args|
      helper.call(self, args, false)
    end
  end
  @path_helpers << path_name
  @url_helpers << url_name
  self
end

def clear! 

def clear!
  @path_helpers.each do |helper|
    @path_helpers_module.remove_method helper
  end
  @url_helpers.each do |helper|
    @url_helpers_module.remove_method helper
  end
  @routes.clear
  @path_helpers.clear
  @url_helpers.clear
end

def define_url_helper(mod, name, helper, url_strategy)


foo_url(bar, baz, bang, sort_by: 'baz')

Also allow options hash, so you can do:

foo_url(bar: bar, baz: baz, bang: bang)

Instead of:

foo_url(bar, baz, bang)

with corresponding dynamic segments, so you can do:
Create a URL helper allowing ordered parameters to be associated 
def define_url_helper(mod, name, helper, url_strategy)
  mod.define_method(name) do |*args|
    last = args.last
    options = \
      case last
      when Hash
        args.pop
      when ActionController::Parameters
        args.pop.to_h
      end
    helper.call(self, name, args, options, url_strategy)
  end
end

def each(&block) 

def each(&block)
  routes.each(&block)
  self
end

def get(name) 

def get(name)
  routes[name.to_sym]
end

def helper_names 

def helper_names
  @path_helpers.map(&:to_s) + @url_helpers.map(&:to_s)
end

def initialize 

def initialize
  @routes = {}
  @path_helpers = Set.new
  @url_helpers = Set.new
  @url_helpers_module  = Module.new
  @path_helpers_module = Module.new
end

def key?(name) 

def key?(name)
  return unless name
  routes.key? name.to_sym
end

def length 

def length
  routes.length
end

def names 

def names
  routes.keys
end

def route_defined?(name) 

def route_defined?(name)
  key = name.to_sym
  @path_helpers.include?(key) || @url_helpers.include?(key)
end