The difference between Ruby alias and alias_method

In some open source ruby projects you may see similar alias and alias_method methods. what are the specific use of these two methods? how are these two methods different? let's look at the following code:

#alias class User def full_name puts "Mixbo" end alias name full_name end User.new.name #=>Mixbo #alias_method class User def full_name puts "Mixbo" end alias_method :name, :full_name end User.new.name #=> Mixbo 

The above examples all output the "Mixbo" string before renaming the full_name in the User class. from this example alone we can't see the difference between the two methods continue:

#alias_method class User def full_name puts "Super Mixbo" end def self.rename alias_method :name, :full_name #==> Note that alias_method is used here end end class Mixbo < User def full_name puts "Mixbooooo" end rename end Mixbo.new.full_name #=> "Mixbooooo" #alias class User def full_name puts "Super Mixbo" end def self.rename alias :name :full_name #==> Note that alias is used here end end class Mixbo < User def full_name puts "Mixbooooo" end rename end Mixbo.new.name #=> 'Super Mixbo' 

From the above example we can see that when there is an inheritance relationship between classes. alias will not affect its subclasses. related alias_method will find the closest method of the same name in its subclass to operate (for example, full_name above)

So alias and alias_method

1. Can give an alias to a method

2. alias is generally valid when the source code is interpreted by the compiler

3. alias_method is generally valid when the code is running

Generally I use alias_method a little more.

Hope it can help you :)