> once you start using those you no longer are able to use libraries This isn't true: if the libraries you use are designed to use generic functions for their

> once you start using those you no longer are able to use libraries This isn't true: if the libraries you use are designed to use generic functions for their internals, rather than normal functions. I've written code using custom data structures heavily, with little or no impact on which libraries I could use. > The common lisp community has rejected reader macros cl21 is just confusing matters here. Plenty of code uses named-readtables to use arbitrary reader macros. I don't understand the "interop reasons" you're talking about: as long as you use named-readtables, interop basically Just Works. > It's also not possible to put those on the wire (easily) for communication between common lisp processes. Breaking the whole point of homoiconicity. Using the reader on untrusted input is a bad idea in either Common Lisp or Clojure, because both readers can execute arbitrary code. However, there are packages like safe-read ( https://github.com/phoe/safe-read https://github.com/phoe/safe-read ) and Eclector ( https://github.com/s-expressionists/eclector https://github.com/s-expressionists/eclector ) that let you solve this problem pretty trivially in a safe way. Not to mention projects like my cl-edn ( https://github.com/fiddlerwoaroof/cl-edn https://github.com/fiddlerwoaroof/cl-edn ).