class ReeMapper::Rational

def cast(value)
  if value.is_a?(Rational)
    value
  elsif value.is_a?(String)
    begin
      Rational(value)
    rescue ArgumentError, ZeroDivisionError
      raise ReeMapper::CoercionError.new("is invalid rational, got `#{truncate(value.inspect)}`")
    end
  elsif value.is_a?(Numeric)
    Rational(value)
  else
    raise ReeMapper::TypeError.new("should be a rational, got `#{truncate(value.inspect)}`")
  end
end

def db_dump(value)
  serialize(value).to_s
end

def db_load(value)
  cast(value)
end

def serialize(value)
  if value.is_a?(Rational)
    value
  else
    raise ReeMapper::TypeError.new("should be a rational, got `#{truncate(value.inspect)}`")
  end
end