是否可以为 to_s 取别名？

Question

Instead of overriding to_s in my model I'd like to alias it to an existing method called full_name .

Both alias and alias_method don't seem to work as expected.

Using alias

class Person < ActiveRecord::Base

  # ... other model code.

  alias to_s full_name

  def full_name
     "#{first_name} #{last_name}"
  end
end

# In Terminal
> Person.last.to_s  #=> "#<Person:0x007fa5f8a81b50>"

Using alias_method

class Person < ActiveRecord::Base

  # ... other model code.

  alias_method :to_s, :full_name

  def full_name
     "#{first_name} #{last_name}"
  end
end

# In Terminal
> Person.last.to_s  #=> "#<Person:0x007fa5f8a81b50>"

Answer 1

Figured it out...

alias and alias_method need to come after the method you are aliasing to.

So both of the following work fine:

Using alias

class Person
  def full_name
     "#{first_name} #{last_name}"
  end

  alias to_s full_name
end

# In Terminal
> Person.last.to_s  #=> "Don Draper"

Using alias_method

class Person
  def full_name
     "#{first_name} #{last_name}"
  end

  alias_method :to_s, :full_name
end

# In Terminal
> Person.last.to_s  #=> "Don Draper"

Hopefully that helps somebody else.