Contents

module MetaExtension
  def self.extended(base)
    meta = class << base; self; end

    base.class_variable_set("@@extension_attrs", [])

    meta.define_method(:extension_attr) do |*attrs|
      self.class_variable_get("@@extension_attrs").concat attrs
      attrs.each do |a|
        self.attr_accessor a
      end
    end

    meta.define_method(:setup) do |obj,*rest|
      obj.extend base
      attrs = self.class_variable_get("@@extension_attrs")

      return if attrs.nil? || attrs.empty?

      if rest.length == 1 && Hash === (rlast = rest.last) && 
          ! (rlkey = rlast.keys.first).nil? &&
          attrs.include?(rlkey.to_sym)

        pairs = rlast
      else
        pairs = attrs.zip(rest)
      end

      pairs.each do |name,value|
        obj.instance_variable_set("@#{name}", value)
      end

      obj
    end

    base.define_method(:annotate) do |other|
      attr_values = meta.class_variable_get("@@extension_attrs").collect do |a|
        self.instance_variable_get("@#{a}")
      end
      base.setup(other, *attr_values)
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
scout-gear-2.0.0	lib/scout/meta_extension.rb
scout-gear-1.2.0	lib/scout/meta_extension.rb