Replace `smartindent` and `smarttab` with custom indent and tab rules

[koibtw]

We need to write full custom indent specification, as smartindent is not great really.
Those rules would include stuff like:

• tab after new scope + newline
• // after comment + newline (?) (rust has that)
• tab after a match case (see here)
• same with labels
• fixing this:
  

Also -1 tab after e.g.:

• ending a scope
• | in a match case
• after a break and other scope-ending keywords

Setting up code folding would also be cool.

That's all off the top of my head but I'm sure there is more to do.

More resources that could help:
https://vimdoc.sourceforge.net/htmldoc/indent.html
https://stackoverflow.com/questions/11747840/creating-custom-vim-syntax-can-i-set-custom-auto-indent-rules

[telemachus]

A few thoughts:

1. For Neovim specifically, you may also want to look into Tree-sitter. (There doesn't seem to be a parser for Jule yet, but Tree-sitter has some advantages over regex-based syntax highlighting and indentation.
2. That said, an indentation/jule.vim file would be good for vanilla Vim and as a fallback for Neovim.
3. More generally, Neovim still pulls in language runtime files from Vim. So a normal way to approach this is to submit a lot of what you have in this repo (translated from Lua to Vimscript) to Vim. Then both Vim and Neovim users would get things like basic filetype detection, syntax highlighting, etc. from Vim's runtime files (even without a more feature-rich plugin).
4. With that in mind, you can probably leverage the Go runtime files in Vim to get a jumpstart on all of this.

All that said, thanks for providing this repo as a way to start using Jule with Neovim. I'm just starting to look at Jule, and this helps.

[koibtw]

thanks for all the suggestions!
i've got a super amazing neovim expert helping me now and we started working on a custom indentexpr for jule!!
i'm also planning on refactoring most of this plugin sometime anyway :)