diff options
Diffstat (limited to 'activesupport/lib/active_support/core_ext/module/attribute_accessors.rb')
| -rw-r--r-- | activesupport/lib/active_support/core_ext/module/attribute_accessors.rb | 174 |
1 files changed, 160 insertions, 14 deletions
diff --git a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb index 672cc0256f..f70a839074 100644 --- a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb +++ b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb @@ -1,10 +1,59 @@ require 'active_support/core_ext/array/extract_options' +# Extends the module object with class/module and instance accessors for +# class/module attributes, just like the native attr* accessors for instance +# attributes. class Module + # Defines a class attribute and creates a class and instance reader methods. + # The underlying the class variable is set to +nil+, if it is not previously + # defined. + # + # module HairColors + # mattr_reader :hair_colors + # end + # + # HairColors.hair_colors # => nil + # HairColors.class_variable_set("@@hair_colors", [:brown, :black]) + # HairColors.hair_colors # => [:brown, :black] + # + # The attribute name must be a valid method name in Ruby. + # + # module Foo + # mattr_reader :"1_Badname " + # end + # # => NameError: invalid attribute name + # + # If you want to opt out the creation on the instance reader method, pass + # <tt>instance_reader: false</tt> or <tt>instance_accessor: false</tt>. + # + # module HairColors + # mattr_writer :hair_colors, instance_reader: false + # end + # + # class Person + # include HairColors + # end + # + # Person.new.hair_colors # => NoMethodError + # + # + # Also, you can pass a block to set up the attribute with a default value. + # + # module HairColors + # cattr_reader :hair_colors do + # [:brown, :black, :blonde, :red] + # end + # end + # + # class Person + # include HairColors + # end + # + # Person.hair_colors # => [:brown, :black, :blonde, :red] + # def mattr_reader(*syms) options = syms.extract_options! syms.each do |sym| - raise NameError.new('invalid attribute name') unless sym =~ /^[_A-Za-z]\w*$/ + raise NameError.new("invalid attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/ class_eval(<<-EOS, __FILE__, __LINE__ + 1) @@#{sym} = nil unless defined? @@#{sym} @@ -20,14 +69,60 @@ class Module end EOS end + class_variable_set("@@#{sym}", yield) if block_given? end end + alias :cattr_reader :mattr_reader + # Defines a class attribute and creates a class and instance writer methods to + # allow assignment to the attribute. + # + # module HairColors + # mattr_writer :hair_colors + # end + # + # class Person + # include HairColors + # end + # + # HairColors.hair_colors = [:brown, :black] + # Person.class_variable_get("@@hair_colors") # => [:brown, :black] + # Person.new.hair_colors = [:blonde, :red] + # HairColors.class_variable_get("@@hair_colors") # => [:blonde, :red] + # + # If you want to opt out the instance writer method, pass + # <tt>instance_writer: false</tt> or <tt>instance_accessor: false</tt>. + # + # module HairColors + # mattr_writer :hair_colors, instance_writer: false + # end + # + # class Person + # include HairColors + # end + # + # Person.new.hair_colors = [:blonde, :red] # => NoMethodError + # + # Also, you can pass a block to set up the attribute with a default value. + # + # class HairColors + # mattr_writer :hair_colors do + # [:brown, :black, :blonde, :red] + # end + # end + # + # class Person + # include HairColors + # end + # + # Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red] def mattr_writer(*syms) options = syms.extract_options! syms.each do |sym| - raise NameError.new('invalid attribute name') unless sym =~ /^[_A-Za-z]\w*$/ + raise NameError.new("invalid attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/ class_eval(<<-EOS, __FILE__, __LINE__ + 1) + @@#{sym} = nil unless defined? @@#{sym} + def self.#{sym}=(obj) @@#{sym} = obj end @@ -40,27 +135,78 @@ class Module end EOS end + send("#{sym}=", yield) if block_given? end end + alias :cattr_writer :mattr_writer - # Extends the module object with module and instance accessors for class attributes, - # just like the native attr* accessors for instance attributes. + # Defines both class and instance accessors for class attributes. # - # module AppConfiguration - # mattr_accessor :google_api_key + # module HairColors + # mattr_accessor :hair_colors + # end # - # self.google_api_key = "123456789" + # class Person + # include HairColors # end # - # AppConfiguration.google_api_key # => "123456789" - # AppConfiguration.google_api_key = "overriding the api key!" - # AppConfiguration.google_api_key # => "overriding the api key!" + # 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>. - # To opt out of both instance methods, pass <tt>instance_accessor: false</tt>. - def mattr_accessor(*syms) - mattr_reader(*syms) - mattr_writer(*syms) + # + # module HairColors + # mattr_accessor :hair_colors, instance_writer: false, instance_reader: false + # end + # + # class Person + # include HairColors + # 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. + # + # module HairColors + # mattr_accessor :hair_colors, instance_acessor: false + # end + # + # class Person + # include HairColors + # 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. + # + # module HairColors + # mattr_accessor :hair_colors do + # [:brown, :black, :blonde, :red] + # end + # end + # + # class Person + # include HairColors + # end + # + # Person.class_variable_get("@@hair_colors") #=> [:brown, :black, :blonde, :red] + def mattr_accessor(*syms, &blk) + mattr_reader(*syms, &blk) + mattr_writer(*syms, &blk) end + alias :cattr_accessor :mattr_accessor end |