ruby - Why the module `ClassMethods` defined and extended in the same namespace? -
i trying understand code github repo. it's main module of gem setup client.
module github # more code class << self def included(base) base.extend classmethods # for? end def new(options = {}, &block) client.new(options, &block) end def method_missing(method_name, *args, &block) if new.respond_to?(method_name) new.send(method_name, *args, &block) elsif configuration.respond_to?(method_name) github.configuration.send(method_name, *args, &block) else super end end def respond_to?(method_name, include_private = false) new.respond_to?(method_name, include_private) || configuration.respond_to?(method_name) || super(method_name, include_private) end end module classmethods def require_all(prefix, *libs) libs.each |lib| require "#{file.join(prefix, lib)}" end end # more methods ... end extend classmethods require_all libdir, 'authorization', 'validations', 'normalizer', 'parameter_filter', 'api', 'client', 'pagination', 'request', 'response', 'response_wrapper', 'error', 'mime_type', 'page_links', 'paged_request', 'page_iterator', 'params_hash' end - why
class << self,module classmethodsused, , extended instead of being included inclass << selfpart? - there class method
def included(base). seems add class methods specific object. why this? relate functionality of class, not understand it.
module mymodule class << self def included(base) base.extend classmethods # for? end <...> end <...> end this pretty common practice in ruby. basically, it's saying is: when object performs include mymodule, make extend mymodule::classmethods. such feat useful if want mixin adds methods not instances of class, class itself.
a short example:
module m # normal instance method def mul @x * @y end module classmethods # class method def factory(x) new(x, 2 * x) end end def self.included(base) base.extend classmethods end end class p include m def initialize(x, y) @x = x @y = y end def sum @x + @y end end p1 = p.new(5, 15) puts "#{p1.sum} #{p1.mul}" # calling class method module here! p2 = p.factory(10) puts "#{p2.sum} #{p2.mul}"
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