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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.
#
# 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
def cattr_reader(*syms)
options = syms.extract_options!
syms.each do |sym|
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
unless defined? @@#{sym}
@@#{sym} = nil
end
def self.#{sym}
@@#{sym}
end
EOS
unless options[:instance_reader] == false
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}
@@#{sym}
end
EOS
end
end
end
def cattr_writer(*syms)
options = syms.extract_options!
syms.each do |sym|
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
unless defined? @@#{sym}
@@#{sym} = nil
end
def self.#{sym}=(obj)
@@#{sym} = obj
end
EOS
unless options[:instance_writer] == false
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}=(obj)
@@#{sym} = obj
end
EOS
end
self.send("#{sym}=", yield) if block_given?
end
end
def cattr_accessor(*syms, &blk)
cattr_reader(*syms)
cattr_writer(*syms, &blk)
end
end
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