Ruby BasicObject methods

Question

while going through Ruby, i encountered that BasicObject is the top most superclass of Class. When I tried BasicObject.methods, i get list of these methods

[:method_missing, :singleton_method_added, :singleton_method_undefined, :singleton_method_removed, :new, :become_java!, :allocate, :superclass, :java_class, :class_variables, :<=, :public_instance_methods, :prepend, :class_variable_get, :public_constant, :singleton_class?, :instance_methods, :freeze, :instance_method, :const_defined?, :to_s, :constants, :ancestors, :private_instance_methods, :===, :included_modules, :==, :using, :class_eval, :const_get, :refine, :protected_instance_methods, :public_instance_method, :class_variable_defined?, :inspect, :name, :private_constant, :<, :hash, :>, :>=, :module_exec, :protected_method_defined?, :module_eval, :const_missing, :class_exec, :const_set, :private_method_defined?, :public_class_method, :autoload, :<=>, :include, :public_method_defined?, :autoload?, :class_variable_set, :include?, :remove_class_variable, :deprecate_constant, :private_class_method, :method_defined?, :include_class, :handle_different_imports, :java_kind_of?, :public_send, :frozen?, :protected_methods, :java_implements, :public_method, :java, :singleton_methods, :untaint, :javafx, :enum_for, :private_methods, :method, :instance_variables, :object_id, :extend, :itself, :instance_variable_set, :respond_to?, :java_name, :methods, :to_java, :java_package, :singleton_class, :public_methods, :to_enum, :display, :tainted?, :instance_variable_defined?, :untrusted?, :define_singleton_method, :!~, :nil?, :com, :instance_of?, :java_require, :javax, :java_signature, :tap, :java_annotation, :send, :trust, :instance_variable_get, :is_a?, :eql?, :java_field, :remove_instance_variable, :untrust, :class, :=~, :org, :taint, :kind_of?, :clone, :dup, :!, :equal?, :instance_exec, :__id__, :instance_eval, :__send__, :!=]

(I have Jruby present as well so some extra methods)

But when I call BasicObject.methods(false) (false parameter for displaying methods of the same class itself), I get

=> [:method_missing, :singleton_method_added, :singleton_method_undefined, :singleton_method_removed]

I have a query, ideally class.methods with false param should return only its methods and BasicObject.superclass returns nil. Is there any other hierarchy? from where does these methods coming from.

I'm learning Ruby Apologozies if i'm missing something. Thanks

Answer 1

You are not asking what instance methods are defined on BasicObject, that would be BasicObject.instance_methods. You are asking, what methods you can call on BasicObject. Well, BasicObject is an object just like any other object, so you can call any method on it that is defined in its class (which in this case is Class) or in the superclasses of its class (which in this case are Module, Object, Kernel, and BasicObject).