Class: Object

Inherits:
BasicObject
Defined in:
lib/concern.rb

Class Method Summary collapse

Class Method Details

.concern(lib, options = {}) ⇒ Object 



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# File 'lib/concern.rb', line 12

def self.concern(lib, options={})
  # load delegate
  lib = lib.to_s
  klass = Concern.classify(lib)
  begin
    klass = eval(klass)
  rescue
    require lib
    klass = eval(klass)
  end

  unless klass.instance_methods.map{|x|x.to_s}.include?('concerned=')
    raise "A concern must always extend Concern"
  end

  # make accessor
  accessor = lib.split('/').last.to_sym
  eval <<-EOF
    def #{accessor}
      return @#{accessor} if @#{accessor}
      @#{accessor} = #{klass}.new
      @#{accessor}.concerned = self
      @#{accessor}
    end
  EOF

  # call included
  base = eval(name) #self.class is always Class, but name is class that called concern
  klass.included(base) if klass.respond_to? :included

  # delegate methods
  if options[:delegate]
    methods = if options[:delegate].is_a?(Array)
      options[:delegate]
    else
      klass.public_instance_methods(false)
    end

    methods.each do |method|
      eval <<-EOF
        def #{method}(*args)
          #{accessor}.#{method}(*args)
        end
      EOF
    end
  end
end