Movement by subwords (snake_case, camelCase, ...)

[JeftavanderHorst]

Helix currently supports moving by both words and WORDS using the w, b and e keys. It might be interesting to add a third kind of word movement: subwords. This would consider the elements of snake_case and camelCase (and perhaps other casings) as separate words.

Example of what I mean (| characters indicate selection):

Moving by word:

• |f|oo bar baz -> press w -> |foo |bar baz
• |f|oo_bar_baz -> press w -> |foo_bar_baz|
• |f|ooBarBaz -> press w -> |fooBarBaz|

Moving by subword:

• |f|oo bar baz -> press w -> |foo |bar baz
• |f|oo_bar_baz -> press w -> |foo_|bar_baz
• |f|ooBarBaz -> press w -> |foo|BarBaz

I'm not sure what appropriate keybindings would be, since both wbe and WBE are already in use. For me personally, I never use WORDS so I would probably remap those keys to subwords, but others might disagree there. In any case, adding the commands (move_next_subword_start, etc) would be useful even if they don't have keybinds by default.

An example of similar behavior in vim is vim-wordmotion.

If people are interested, I might have time to work on a PR for this.

[themissingcow]

I'd find this really valuable - it's one of the reasons I still use neovim at work. I don't know Rust but, I'd love to help work on this.

[JeftavanderHorst]

For anyone stumbling upon this discussion, I opened a PR for this here: #8147