Class: Module

Inherits:
Object
  • Object
show all
Defined in:
lib/cgen/inherit.rb

Defined Under Namespace

Classes: InheritError

Instance Method Summary collapse

Instance Method Details

#inherit(parent, *methods) ⇒ Object

Called in the context of a class or module, #inherit establishes a secondary inheritance path via #parent. The arguments should be strings or symbols; #parent can refer to an attribute or method with no arguments. The listed methods are given definitions in the base class or module which simply pass the message, along with any arguments and an optional block, to the parent, or throw an InheritError if there is none. For example:

module M
  inherit :@parent, :foo
end

class A
  def foo
    "FOO"
  end
end

class B
  include M
  def initialize
    @parent = A.new
  end
end

print B.new.foo # ==> "FOO"



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# File 'lib/cgen/inherit.rb', line 30

def inherit parent, *methods
  local_var = parent.to_s.sub(/^@?/, "_")
  methods.each do |m|
    module_eval %{
      undef #{m} rescue nil
      def #{m}(*args, &block)
        #{local_var} = #{parent}
        if #{local_var}
          #{local_var}.#{m}(*args, &block)
        else
          raise InheritError, "No #{parent} handles #{m}."
        end
      end
    }
  end
end