[dkarl]

By "replacing" lists with trees, am I supposed to understand that working with trees will be natural and easy, and lists will feel like second-class citizens? I thought we were beyond thinking like that. Building languages around a favorite data structure was never the right thing to do; it was always tunnel vision and bad design. Different data structures have different features and different performance characteristics. There's no reason for a language designer to pick a favorite data structure and force anyone who has to use a different one to deal with warts and second-class library and language support.