Add a variant of sub-selection (s) that uses textobjects instead of regex

[EpocSquadron]

I think it could be very ergonomic to be able to have a selection broken down by tree-sitter driven textobjects that can give us commonly desired selections.

Consider a selection like the following:

//                  [                   selection                           |]
function doSomething($firstParam, MyTypeHint $secondParam, $thirdParam = null) {
    // do something
}

If you want to select all parameters to the function, say so you could reorder them with Alt-) or append a new line to each to begin reformatting them, you would need to split on spaces with S <enter>, but this will incorrectly split the selection where the default value is defined, and where the typehint is included.

With this proposal, you could enter the new subselection mode (keybind to be determined), and enter a meaning the textobject for parameters/arguements, resulting in the following selections:

//                   [   sel1  |] [         sel2        |] [      sel3     |]
function doSomething($firstParam, MyTypeHint $secondParam, $thirdParam = null) {
    // do something
}

Similar to the mi/ma and ]/[ binds, this new bind would show an autoinfo of possible textobjects, rather than prompting for a regex as the current s and S keybind does.

[CBenoit]

Hi @the-mikedavis
FYI I was thinking about implementing this if it’s okay (I see you assigned yourself for #3263)

[the-mikedavis]

Sweet! I think the changes for #3263 will end up being separate from this so I don't think we'll step on each others' toes 🙂

[EpocSquadron]

For keybinds, I wonder if the existing behavior of s/S can be moved to the autoinfo alongside the textobjects, with / being the triggering option.

[pascalkuthe]

I would love to see this, @CBenoit did you make any progress on this otherwise I might take this on soonish (altough I quite a few other things I want to finish first)

For keybinds, I wonder if the existing behavior of s/S can be moved to the autoinfo alongside the textobjects, with / being the triggering option.

I would rather see this as a seperate keybinding. s is likely one of the most common keybindings I use in helix, it's so insanely useful and I would want to keep it as a single-key hotkey. Perhaphs an uppercase version might be an option: mI/mA uppercase characters for alternative behaviour seems to be a pattern we are moving towrads in general it sems. What do you think @the-mikedavis?

[EpocSquadron]

I would suggest alt-s but I think it's a bit to unergonomic for a potentially often used feature, plus there's discussion around using that binding for #2413.

[the-mikedavis]

Figuring out a good keybind for this is tricky. I have a slight preference for putting this under m (maybe mS or m/?). We may also want a "keep" variant of this command like K though which makes it even tricker to find a good binding.