module PR
  class BuildModel
    def self.[] form, model
      new(PR::FieldRegistry[form.class]).for form, model
    end

    def initialize registry
      @registry = registry
    end

    def for form, model
      @registry.fields.each do |field_name|
        set model, field_name, value(form, field_name)
      end
    end

    private
      def set thing, name, value
        thing.send "#{name}=", value
      end
      def value thing, name
        thing.send("__#{name}").convert
      end

  end
end