Maybe not important to some but the ability to use Lua over VimScript is a big win in my opinion. In fact, I use a mix of thr two where necessary.
Vimscript's dominance in vim is one of the things that got me to switch to emacs when I got interested in Lisp and Scheme more than a decade ago.
Sure, even then I could write scripts for vim using Vim's scheme compatibility mode, but I'd probably be one of the only ones doing so. Pretty much everyone else was using vimscript.
In Emacs the whole ecosystem is in eLisp, so I'd feel right at home there, could naturally integrate other eLisp codebases/projects, could easily get help on anything related to working with eLisp in emacs.
If I'd written scheme scripts in vim my work would always be a second-class citizen in the vim ecosystem.
How's the vim ecosystem now? Is vimscript still dominant?
You can have a full neovim experience with all sorts of modern extensions without using a single line of vimscript. Some people even replace their init (neovim's vimrc) with lua, but I am of the opinion that it is a step too far, as lua isn't particularly adapted to writing configuration files and the result is too verbose to my taste.
I use lua when examples are in lua or when I need some "logic" (such as assigning defaults to a var and then passing that around/overriding). And that's embedded in vimscript.
I don't really like either. VimScript has always been a horror to me, eventhough I've been using vim for some 20 years now, almost exclusively. Lua is "that thing that I should really sit down and learn. But not now, I've got stuff to finish".
What does lua -for an end user- offer that something like yaml+python cannot offer? I really won't mind setting all sorts of flags, defaults and vars from some init.yaml, and then have some init.py to handle the few places where I do need actual logic. Why was lua picked, why did vim build its own language and not move to an existing one for its config? Am I just weird for never sitting down and learning lua? Or vimscript? Or both?
Why Bram build is own language and then doubled down on it with vimscript9 I don't really understand.
[1] https://neovim.discourse.group/t/why-was-lua-chosen-for-neov...
What language would have you chosen in 1991 instead of creating vimscript? The vimscript language is a very natural extension[0] of Bill Joy's "ex" language, that was used in vi since 1976. The history of vimscript is not weird, it's just a fairly natural continuation of existing practices. Vimscript9 is a least-friction update for modern times.
[0] https://en.wikipedia.org/wiki/Vim_(text_editor)#Vim_script
According to your link scripting was only available from '98, at which point Lua and Python were already around, but then I don't know how viable that would have been. Funny you say that about ex, because I find running ex commands from vimscript the most clunky thing about it.
In my opinion the least friction for the ecosystem would have been to follow neovim and adapt Lua.
[0]: a Lisp that compiles to Lua, https://github.com/bakpakin/Fennel
The Neovim people went a bit further with the integration, but you've been able to use Lua with Vim for like 20 years or so, and you can use it to write perfectly functional plugins with it. Probably the main difference is that in Neovim Lua is always guaranteed to be available, which isn't the case for Vim.