Still deciding if I buy it. only wants 1000 bucks a month to work on it full time, I think exploring the area is worth that at least.
I hit page-down 40 times and wasn't even halfway through. I feel like billing $1000 to skim the proposal.
I don't think there's an argument to be had for all structures, just that you can do it for each custom structure, and that's the point.
Maybe the editors of the old tried to bite off too much when they attempted embedded structures, and they didn't have the right abstractions in place. If you look at https://tylr.fun it shows that things that weren't being done back then, there are interesting approaches now.
Emacs modes, in other words?
Like how, in Emacs, C-n nearly always does "move to next line" but it could mean "highlight next mail message" and "Enter" nearly always does something with the current line but it could mean "open currently highlighted message" or "newline and indent as per language-specific rules" or "send this line to a subprocess" or whatever.
Modes don't do that. Neither do they let you control the underlying structure, they give you no ability to treat structures as objects. Yes, they do provide a common interface, but that's where the pros end. Ofc its emacs, and there are projects like Multi-Major-Modes that at least try to subdivide a document into editable areas... speaking of ridiculously slow.
As for constraints and prototype OO: I think those will simply do great for GUI building, and for flexibility. I think you need such abstractions to be able to deal with customization and complexity of embedded structures. I am basing Fern on the Garnet GUI framework [1], which had ~80 projects and was pretty fun to use judging by what people say.
I don't understand the criticism about Cider: I use it daily.
Emacs 29 with libjansson and native-compilation is plenty fast.
And most of all: apparently every single new version of Emacs not only runs but also compiles faster. And this is coupled with my computers which only gets faster too.
At the moment I'm running Emacs 29 on a AMD 3700X, soon to be replaced with a 7700 or 7700X. That's going to be yet another performance gain.
Most software only get slower and slower with each release (I was already using IntelliJ IDEA back when it was a version 4 and already bloated, since then it's been downhill perf-wise): Emacs, on the contrary, always keeps getting faster.
And the goodies added to Emacs lately are just insane: native-compilation, LSP support, tree-sitter (it's just been included in Emacs and it should bring yet another round of crazy speedups)...