Just curious what didn’t work with Sexpq ? I didn’t follow closely but I don’t see what you couldn’t possibly express.
That’s one of problem with s-expressions. There is no well defined encoding of dictionnaries, or rather people who write them by hand do not want to use the clean ones.
In lisp you would write them as a list of bindings, a binding being (key . <s-exp>).
In config files it seems no one wants to write that .. You could do (key <s-exp>) but it seems again no one wants to write the extra parens when you bind a key to a list.
So we end up with this bastardized notion of binding which is not so great since you can no longer distinguish between a binding to a singleton list and a binding to an atom without external knowledge (it also makes substitution and other operations harder than it could be).