+1. I want a book that walks me through a real, well designed, functional (if you pardon the pun), useful piece of software, end to end. All these FP books are

+1. I want a book that walks me through a real, well designed, functional (if you pardon the pun), useful piece of software, end to end. All these FP books are too enamored with language features, instead of showing you how a programmer proficient in the language would solve practical problems in it.