diff options
Diffstat (limited to 'activesupport/lib/active_support/core_ext/class/attribute_accessors.rb')
| -rw-r--r-- | activesupport/lib/active_support/core_ext/class/attribute_accessors.rb | 134 |
1 files changed, 111 insertions, 23 deletions
diff --git a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb index 5cb528cfe9..fa1dbfdf06 100644 --- a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb +++ b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb @@ -2,30 +2,33 @@ require 'active_support/core_ext/array/extract_options' # Extends the class object with class and instance accessors for class attributes, # just like the native attr* accessors for instance attributes. -# -# Note that unlike +class_attribute+, if a subclass changes the value then that would -# also change the value for parent class. Similarly if parent class changes the value -# then that would change the value of subclasses too. -# -# class Person -# cattr_accessor :hair_colors -# end -# -# Person.hair_colors = [:brown, :black, :blonde, :red] -# Person.hair_colors # => [:brown, :black, :blonde, :red] -# Person.new.hair_colors # => [:brown, :black, :blonde, :red] -# -# To opt out of the instance writer method, pass :instance_writer => false. -# To opt out of the instance reader method, pass :instance_reader => false. -# To opt out of both instance methods, pass :instance_accessor => false. -# -# class Person -# cattr_accessor :hair_colors, :instance_writer => false, :instance_reader => false -# end -# -# Person.new.hair_colors = [:brown] # => NoMethodError -# Person.new.hair_colors # => NoMethodError class Class + # Defines a class attribute if it's not defined and creates a reader method that + # returns the attribute value. + # + # class Person + # cattr_reader :hair_colors + # end + # + # Person.class_variable_set("@@hair_colors", [:brown, :black]) + # Person.hair_colors # => [:brown, :black] + # Person.new.hair_colors # => [:brown, :black] + # + # The attribute name must be a valid method name in Ruby. + # + # class Person + # cattr_reader :"1_Badname " + # end + # # => NameError: invalid attribute name + # + # If you want to opt out the instance reader method, you can pass <tt>instance_reader: false</tt> + # or <tt>instance_accessor: false</tt>. + # + # class Person + # cattr_reader :hair_colors, instance_reader: false + # end + # + # Person.new.hair_colors # => NoMethodError def cattr_reader(*syms) options = syms.extract_options! syms.each do |sym| @@ -50,6 +53,43 @@ class Class end end + # Defines a class attribute if it's not defined and creates a writer method to allow + # assignment to the attribute. + # + # class Person + # cattr_writer :hair_colors + # end + # + # Person.hair_colors = [:brown, :black] + # Person.class_variable_get("@@hair_colors") # => [:brown, :black] + # Person.new.hair_colors = [:blonde, :red] + # Person.class_variable_get("@@hair_colors") # => [:blonde, :red] + # + # The attribute name must be a valid method name in Ruby. + # + # class Person + # cattr_writer :"1_Badname " + # end + # # => NameError: invalid attribute name + # + # If you want to opt out the instance writer method, pass <tt>instance_writer: false</tt> + # or <tt>instance_accessor: false</tt>. + # + # class Person + # cattr_writer :hair_colors, instance_writer: false + # end + # + # Person.new.hair_colors = [:blonde, :red] # => NoMethodError + # + # Also, you can pass a block to set up the attribute with a default value. + # + # class Person + # cattr_writer :hair_colors do + # [:brown, :black, :blonde, :red] + # end + # end + # + # Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red] def cattr_writer(*syms) options = syms.extract_options! syms.each do |sym| @@ -75,6 +115,54 @@ class Class end end + # Defines both class and instance accessors for class attributes. + # + # class Person + # cattr_accessor :hair_colors + # end + # + # Person.hair_colors = [:brown, :black, :blonde, :red] + # Person.hair_colors # => [:brown, :black, :blonde, :red] + # Person.new.hair_colors # => [:brown, :black, :blonde, :red] + # + # If a subclass changes the value then that would also change the value for + # parent class. Similarly if parent class changes the value then that would + # change the value of subclasses too. + # + # class Male < Person + # end + # + # Male.hair_colors << :blue + # Person.hair_colors # => [:brown, :black, :blonde, :red, :blue] + # + # To opt out of the instance writer method, pass <tt>instance_writer: false</tt>. + # To opt out of the instance reader method, pass <tt>instance_reader: false</tt>. + # + # class Person + # cattr_accessor :hair_colors, instance_writer: false, instance_reader: false + # end + # + # Person.new.hair_colors = [:brown] # => NoMethodError + # Person.new.hair_colors # => NoMethodError + # + # Or pass <tt>instance_accessor: false</tt>, to opt out both instance methods. + # + # class Person + # cattr_accessor :hair_colors, instance_accessor: false + # end + # + # Person.new.hair_colors = [:brown] # => NoMethodError + # Person.new.hair_colors # => NoMethodError + # + # Also you can pass a block to set up the attribute with a default value. + # + # class Person + # cattr_accessor :hair_colors do + # [:brown, :black, :blonde, :red] + # end + # end + # + # Person.class_variable_get("@@hair_colors") #=> [:brown, :black, :blonde, :red] def cattr_accessor(*syms, &blk) cattr_reader(*syms) cattr_writer(*syms, &blk) |