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require "active_support/core_ext/array/extract_options"
require "active_support/core_ext/regexp"
# 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 class variable is set to +nil+, if it is not previously
# defined. All class and instance methods created will be public, even if
# this method is called with a private or protected access modifier.
#
# 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: 1_Badname
#
# 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_reader :hair_colors, instance_reader: false
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors # => NoMethodError
#
# You can set a default value for the attribute.
#
# module HairColors
# mattr_reader :hair_colors, default: [:brown, :black, :blonde, :red]
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors # => [:brown, :black, :blonde, :red]
def mattr_reader(*syms, instance_reader: true, instance_accessor: true, default: nil)
syms.each do |sym|
raise NameError.new("invalid attribute name: #{sym}") unless /\A[_A-Za-z]\w*\z/.match?(sym)
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
@@#{sym} = nil unless defined? @@#{sym}
def self.#{sym}
@@#{sym}
end
EOS
if instance_reader && instance_accessor
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}
@@#{sym}
end
EOS
end
sym_default_value = (block_given? && default.nil?) ? yield : default
class_variable_set("@@#{sym}", sym_default_value) unless sym_default_value.nil?
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. All class and instance methods created
# will be public, even if this method is called with a private or protected
# access modifier.
#
# 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
#
# You can set a default value for the attribute.
#
# module HairColors
# mattr_writer :hair_colors, default: [:brown, :black, :blonde, :red]
# end
#
# class Person
# include HairColors
# end
#
# Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
def mattr_writer(*syms, instance_writer: true, instance_accessor: true, default: nil)
syms.each do |sym|
raise NameError.new("invalid attribute name: #{sym}") unless /\A[_A-Za-z]\w*\z/.match?(sym)
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
@@#{sym} = nil unless defined? @@#{sym}
def self.#{sym}=(obj)
@@#{sym} = obj
end
EOS
if instance_writer && instance_accessor
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}=(obj)
@@#{sym} = obj
end
EOS
end
sym_default_value = (block_given? && default.nil?) ? yield : default
send("#{sym}=", sym_default_value) unless sym_default_value.nil?
end
end
alias :cattr_writer :mattr_writer
# Defines both class and instance accessors for class attributes.
# All class and instance methods created will be public, even if
# this method is called with a private or protected access modifier.
#
# module HairColors
# mattr_accessor :hair_colors
# end
#
# class Person
# include HairColors
# end
#
# HairColors.hair_colors = [:brown, :black, :blonde, :red]
# HairColors.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.new.hair_colors << :blue
# Person.new.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>.
#
# 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_accessor: false
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors = [:brown] # => NoMethodError
# Person.new.hair_colors # => NoMethodError
#
# You can set a default value for the attribute.
#
# module HairColors
# mattr_accessor :hair_colors, default: [:brown, :black, :blonde, :red]
# end
#
# class Person
# include HairColors
# end
#
# Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
def mattr_accessor(*syms, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil, &blk)
mattr_reader(*syms, instance_reader: instance_reader, instance_accessor: instance_accessor, default: default, &blk)
mattr_writer(*syms, instance_writer: instance_writer, instance_accessor: instance_accessor, default: default)
end
alias :cattr_accessor :mattr_accessor
end
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