argonaut-io/argonaut — pull request #133 by chrislewis (2014-08-24 15:53:41+00:00)
Title: add filter and withFilter alias on DecodeResult

Original motivation was wanting a slightly more humane way of filtering json that parsed successfully, yet may not represent a valid value. For example, if a string value is used to represent case objects and we need to make sure this value maps to one of them, pattern guards are convenient means to do so.