Method: Module#copy_inheritor

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

#copy_inheritor(name, default = {}) ⇒ Object

Like #class_inheritor but non-dynamic. The value of the inheritor is copied from the ancestor on first read.

c = Class.new do
  def self.x; ['x']; end
end

d = Class.new(c) do
  copy_inheritor :x
end

d.x  #=> ['x']

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

CREDIT: Thomas Sawyer

Uncommon:

  • require ‘facets/module/copy_inheritor’



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# File 'lib/core/facets/module/copy_inheritor.rb', line 26

def copy_inheritor(name, default={})
  class_extend do
    define_method(name) do
      if instance_variable_defined?("@#{name}")
        instance_variable_get("@#{name}")
      else
        if anc = ancestors[1..-1].find{ |a| a.respond_to?(name) }
          value = anc.__send__(name)
          value = value.dup rescue value
          instance_variable_set("@#{name}", value)
        else
          instance_variable_set("@#{name}", default)
        end
      end
    end
  end
end