virtus-map-wrappers.rb

require "virtus"

class FinancialDocumentStatus
  def initialize(status_string)
    @status_string = status_string
  end

  def settled?
    true
  end
end

class Payment
  include Virtus

  attribute :status, FinancialDocumentStatus, writer_class: MapValue(FinancialDocumentStatus)
end

# Generator of writers to simply wrap value into
# desired class
#
# @param [Class] klass
#   type to which you want to map your attribute values
#
# @return [Class]
#   class which implements Virtus::Attribute::Writer::Coercible API
#
def MapValue(klass)
  Class.new(Virtus::Attribute::Writer::Coercible).tap do |writer|
    writer.class_eval <<-EOV, __FILE__, __LINE__ + 1
      def coerce(value)
        return unless value

        #{klass.name}.new(value)
      end
    EOV
  end
end