Method: Module#cattr_writer

Defined in:
lib/core/facets/module/mattr.rb

#cattr_writer(*syms) ⇒ Object

Creates a class-variable attr_writer that can be accessed both on an instance and class level.

class CAWExample
  cattr_writer :a
  def self.a
    @@a
  end
end

CAWExample.a = 10
CAWExample.a            #=> 10
CAWExample.new.a = 29
CAWExample.a            #=> 29

NOTE: This method is not a common core extension and is not loaded automatically when using require 'facets'.

CREDIT: David Heinemeier Hansson

Uncommon:

  • require ‘facets/module/cattr’



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# File 'lib/core/facets/module/mattr.rb', line 94

def cattr_writer(*syms)
  syms.flatten.each do |sym|
    module_eval(<<-EOS, __FILE__, __LINE__)
      unless defined? @@#{sym}
        @@#{sym} = nil
      end

      def self.#{sym}=(obj)
        @@#{sym} = obj
      end

      def #{sym}=(obj)
        @@#{sym}=(obj)
      end
    EOS
  end
  return syms
end