Marks

[the-mikedavis]

Marks are a way of recording selections/ranges in a way that can be used later. It's like the ability to store jumplist entry in a registers plus commands to combine selections to/from registers. This PR implements kakoune's marks commands and also adds a function that joins the ranges of a given selection together.

I would like to explore basing LSP snippets on marks so I'll keep this as a draft for now.

Questions:

• The implementation (prior to this change) knows "multiple selections" as one helix_core::selection::Selection with many helix_core::selection::Ranges. Colloquially we call this multiple selections though. Should the marks commands say "selections" or "ranges"?
• Where to put the marks commands? z/Z is taken and the normal mode keymap is pretty much full. I'm using ^ for now which is a bit hidden but it's nice that it matches the default marks register.

Closes #703

[EpocSquadron]

IMHO, Range should be renamed to Selection in code for confirmation with how is referred to colloquially. Correspondingly, Selection should be renamed simply to Selections, plural. But that's probably a separate PR. Regardless I think the user facing language should follow what people are saying.

[EpocSquadron]

There's some really interesting discussion about how kakoune's marks could be improved or generalized in this post on the kakoune discourse that I think should be thought through before we commit to exactly the current kakoune implementation here. I'd like our version to be an improvement rather than just a copy.

[the-mikedavis]

The top-level folding ideas look like marks ideas applied to the ranges of the current selection (rather than the current selection and the selection in the register). ^j in this PR implements <A-r>u. I'm not sure intersection makes sense since you can't have overlapping ranges in a single selection. It could be used as the space between all consecutive ranges in a selection I suppose.

Since only s/S are taken under ^ currently, we could rename ^j as ^u and implement the rest to act on the ranges in the current selection only.

I'm not sure I like the reduce idea with |, it seems too specific and I'm having a hard time imagining a useful use-case for it.

[EpocSquadron]

I'm still chewing on adding operations on the current selections. I agree intersection makes little sense there, and at least left and right most are achievable with a combination of (/) and ,. Longest and shortest could theoretically be useful after s with a regex giving variable length matches, but it's pretty niche.

I agree that the pipe thing as presented is too complicated and niche. There's something to being able to iterate and accumulate over contents of current selections, but that's best as a separate issue.

In the meantime I found the original issue where z/Z was chosen and apparently it started as ^ too. I kind of agree it's not super ergonomic. What about $? Looks like the s in selections, and we could use that as the default register instead of ^. Perhaps even less ergonomic though.

[EpocSquadron]

One operation missing that has a lot of discussion in kakoune is adding the difference operation.

[goyalyashpal]

can this one be considered closed?

[VKondakoff]

So, is the marks feature abandoned?

[the-mikedavis]

I haven't looked at this or worked on it in a while. It's still a useful feature I'd like to see implemented eventually but I don't plan to work on it any time soon. So I'll close this out.

Anyone interested can pick up this PR but it needs some work: we need to map the saved ranges through changes to their documents.