A few months ago, Damien Cassou announced his hierarchy.el library. It looks like it went a bit under the radar in the Emacs community – I haven’t heard about it much since. That’s a pity, since it looks quite interesting. It is a generic library of functions to work with tree-like structures. The most interesting thing from my perspective (since I don’t do much Elisp coding nowadays) is the ability to display hierarchies and navigate them interactively. Since I have a need to examine some JSON data from time to time, json-navigator (one of the examples of using the hierarchy library) is especially handy for me.
While it has some rough edges and is a bit more like a proof-of-concept than a polished tool, it is useful nevertheless. Also, it has two entry points: json-navigator-navigate-region (which does what it says on the tin) and json-navigator-navigate-after-point, which is really handy. Since I quite often deal with large-ish CSV files where some of the cells are pretty deep json structures, I like it very much that I don’t have to mark the json myself. (Especially that M-f and its cousins do not respect braces in CSV mode, which is reasonable but annoying in this particular case.)