Ruby/Reflection/respond to

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Содержание

Check respond_to? for new added instance method

class MyClass
  def MyClass.my_singleton_method
 end
  def my_instance_method
  end
end
p MyClass.respond_to? :my_instance_method       # => false



Check respond_to? for new added singleton method

class MyClass
  def MyClass.my_singleton_method
 end
  def my_instance_method
  end
end
p MyClass.respond_to? :my_singleton_method      # => true



Testing Whether an Object Is String-like

"A string".respond_to? :to_str              # => true
Exception.new.respond_to? :to_str           # => true
4.respond_to? :to_str                       # => false



The method respond_to? tests to see whether an instance of Address has access to :given_name, inherited from the Name class.

#!/usr/bin/env ruby
class Name
  attr_accessor :given_name, :family_name
end
class Address < Name
  attr_accessor :street, :city, :state, :country
end
a = Address.new
puts a.respond_to?(:given_name) # => true



The respond_to? method from Object checks to see if a given object responds to a given method.

class A
  attr_accessor :x
end
a = A.new
a.respond_to? :x # => true
a.respond_to? :x= # => true
a.respond_to? :y # => false
Источник — «http://wiki.crossplatform.ru/index.php?title=Ruby/Reflection/respond_to»