List of callback methods

If you ever wondered about the power of method\_missing you were still missing a lot. Ruby has a whole bunch of meta callback methods. Since I always forget some of them, I will try to collect all of them in the following list, so everybody may benefit. If I missed something, please give me a hint.

Class	Name	corresponds to
Module	included
Module	extended
Module	append_feature	include?
Module	const_missing	const_defined?
Module	method_added
Module	method_removed
Module	method_undefined
Class	inherited
Object	singleton_method_added
Object	singleton_method_removed
Object	singleton_method_undefined
Kernel	at_exit
Kernel	method_missing	respond_to?
Kernel	set_trace_func
Kernel	trace_var
Kernel	untrace_var
ObjectSpace	each_object

Most of this list is taken from this discussion on ruby-talk.

And of course there are all these nice collections, you may request.

Class	Name	include super
Module	ancestors
Module	constants
Module	included_modules
Module	instance_methods	true
Module	private_instance_methods	true
Module	protected_instance_methods	true
Module	public_instance_methods	true
Module	class_variables
Class	superclass
Object	methods
Object	private_methods	true
Object	protected_methods	true
Object	public_methods	true
Object	singleton_methods	true
Object	instance_variables

Please note, that most of the \*methods have a parameter, which allows you to exclude inherited properties from the answer (as listed in the table).

Every ambitous Ruby programmer should have a look at these and come back each one or two months. These methods will allow you some shortcuts and more elegant solutions. As well, make sure, that these still work, after you introduced changes on the meta-level.