moosey-fate.rb

module MooseyFate
  def self.included(c)
    c.define_singleton_method :has do |name, attributes = {}|
      unless defined? @__moosey_attrs
        @__moosey_attrs = []
      end

      attributes[:name] = name.to_sym

      ivar = ('@' + name.to_s).to_sym

      define_method name.to_sym do
        instance_variable_get ivar
      end

      define_method (name.to_s + '=').to_sym do |value|
        instance_variable_set ivar, value
      end

      @__moosey_attrs.push attributes
    end

    c.define_singleton_method :attributes do
      attributes = superclass.include?(MooseyFate) ? superclass.attributes.dup : []

      if defined? @__moosey_attrs
        attributes.concat(@__moosey_attrs.map { |attr| attr[:name] })
      end

      attributes
    end

    c.class_eval do
      define_method :initialize do |params|
        if self.class.superclass.include?(MooseyFate)
          super(params)
        end

        attrs = self.class.instance_eval do
          if defined? @__moosey_attrs
            @__moosey_attrs
          else
            []
          end
        end

        attrs.each do |attr|
          name = attr[:name]
          if params.has_key? name
            value = params[name]
            if attr.has_key? :from_document then
              value = attr[:from_document].call(value)
            end
            ivar  = ('@' + name.to_s).to_sym

            instance_variable_set ivar, value
          end
        end
      end
    end
  end
end