instance method `alias_attribute`

Ruby on Rails 7.0.10

Since v3.0.20

Available in: v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

alias_attribute(new_name, old_name)

Allows you to make aliases for attributes.

class Person
  include ActiveModel::AttributeMethods

  attr_accessor :name
  attribute_method_suffix '_short?'
  define_attribute_methods :name

  alias_attribute :nickname, :name

  private
    def attribute_short?(attr)
      send(attr).length < 5
    end
end

person = Person.new
person.name = 'Bob'
person.name            # => "Bob"
person.nickname        # => "Bob"
person.name_short?     # => true
person.nickname_short? # => true

Parameters

new_name req
old_name req

Source

# File activemodel/lib/active_model/attribute_methods.rb, line 204
      def alias_attribute(new_name, old_name)
        self.attribute_aliases = attribute_aliases.merge(new_name.to_s => old_name.to_s)
        ActiveSupport::CodeGenerator.batch(self, __FILE__, __LINE__) do |code_generator|
          attribute_method_matchers.each do |matcher|
            method_name = matcher.method_name(new_name).to_s
            target_name = matcher.method_name(old_name).to_s
            parameters = matcher.parameters

            mangled_name = target_name
            unless NAME_COMPILABLE_REGEXP.match?(target_name)
              mangled_name = "__temp__#{target_name.unpack1("h*")}"
            end

            code_generator.define_cached_method(method_name, as: mangled_name, namespace: :alias_attribute) do |batch|
              body = if CALL_COMPILABLE_REGEXP.match?(target_name)
                "self.#{target_name}(#{parameters || ''})"
              else
                call_args = [":'#{target_name}'"]
                call_args << parameters if parameters
                "send(#{call_args.join(", ")})"
              end

              modifier = matcher.parameters == FORWARD_PARAMETERS ? "ruby2_keywords " : ""

              batch <<
                "#{modifier}def #{mangled_name}(#{parameters || ''})" <<
                body <<
                "end"
            end
          end
        end
      end

Defined in activemodel/lib/active_model/attribute_methods.rb line 204 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveModel::AttributeMethods::ClassMethods

Signature

Parameters