Support <c-h> in g:AutoPairsMapBS (and ps, thanks!)

[sodapopcan]

Hiya @LunarWatcher,

I just switched to this plugin after several years of using Kana's smartinput plugin. I knew I had to switch no matter what as soon as I read "1. Upgrade to Vim" in the README 🤣 So far it's working great and fixes an issue I always had with smartinput but never bothered reporting since it seemed largely unmaintained (i_<CR> did not work for square brackets).

One thing that did work in smartinput is using <c-h> as backspace (to delete closing pair) which I do all the time (less of a stretch!). I'm happy to make a PR but thought I'd ask first (also happy to let you do it if you'd prefer).

More controversially (and this is something that didn't work in smartinput either): I'm a user of rsi.vim so on top of <c-h> I also sometimes hit <c-w> hoping it will also delete the closing bracket. I'm totally onboard with being conservative and not checking for the presence of other plugins (especially since <c-w> conflicts with the default termkey) but I thought I would ask!

Thanks for the great plugin and the lolz :)

Andrew

[sodapopcan]

PS, I just experienced it working with """ as well! I could cry 🥲 Even the way """ auto-pairs is nicer. I'm going to have to untrain my """<cr><esc>O muscle memory but that is nice problem to a very nice problem to have :)

[LunarWatcher]

Thanks for the great plugin and the lolz :)

You're welcome :) Always nice to hear it's being used ^^

---

I don't think I want to add <C-h> back, largely just because it's an extra two config options for minimal value for most people.

What you can do, however, is add this to your vimrc:

imap <C-h> <BS>

That'll recursively remap <C-h> to <BS> , so as long as you set g:AutoPairsBS = 1, it'll delete pairs. As an added bonus, it'll work as backspace everywhere, even if you eventually uninstall auto-pairs, and (in theory) work with anything else mapped to <BS>, if anything - as long as the <BS> maps are well-defined anyway, but that's a tangent.

---

As for <C-w>, this is more involved, but something I would be interested in supporting.

Not sure what <C-w> is for you (if it differs from the standard), but it's commonly used for word deletion, so preserving default behaviour would be nice here.

Right now, <BS> is hard-coded in AutoPairsDelete in multiple places:

auto-pairs/autoload/autopairs.vim

Lines 253 to 316 in 2c18fa6

	return "\<BS>"
	end
	let [before, after, ig] = autopairs#Strings#getline(b:AutoPairsMultilineBackspace)
	if b:AutoPairsBSIn == 1
	for [open, close, opt] in b:AutoPairsList
	if !opt["delete"] || close == ''
	" Non-deletable pairs? Skip 'em
	continue
	endif
	let rest_of_line = opt['multiline'] ? after : ig
	let b = matchstr(before, autopairs#Utils#escape(open, opt) .. '\v\s?$')
	let a = matchstr(rest_of_line, '^\v\s*' .. autopairs#Utils#escape(close, opt))
	if b != '' && a != ''
	if b[-1:-1] == ' '
	if a[0] == ' '
	return "\<BS>\<DELETE>"
	else
	return "\<BS>"
	end
	end
	return autopairs#Strings#backspace(b) .. autopairs#Strings#delete(a)
	end
	endfor
	endif
	if b:AutoPairsBSAfter == 1
	" delete the pair foo[]| <BS> to foo
	for [open, close, opt] in b:AutoPairsList
	if !opt["delete"]
	continue
	endif
	if (close == '')
	continue
	endif
	let m = autopairs#Strings#matchend(before, autopairs#Utils#escape(open, opt) .. '\v\s*' .. autopairs#Utils#escape(close, opt) .. '\v$', 0)
	if len(m) > 0
	return autopairs#Strings#backspace(m[2])
	elseif opt["multiline"] && b:AutoPairsMultilineBackspace
	let m = matchstr(before, '^\v\s*' .. autopairs#Utils#escape(close, opt))
	if m != ''
	let b = ""
	let offset = 1
	" a = m
	while getline(line('.') - offset) =~ "^\s*$"
	let b ..= getline(line('.') - offset) .. ' '
	let offset += 1
	if (line('.') - offset <= 0)
	return "\<BS>"
	endif
	endwhile
	let a = matchstr(getline(line('.') - offset), autopairs#Utils#escape(open, opt) .. '\v\s*$') .. ' '
	if a != ' '
	return autopairs#Strings#backspace(a) .. autopairs#Strings#backspace(b) .. autopairs#Strings#backspace(m)
	endif
	endif
	end
	endfor
	endif
	return "\<BS>"

Some, but not all, need to be replaced with a variable, and I'm not sure which (aside the ones on line 253 and 316 - I haven't looked at that code in ages, and most of it remains undocumented dark magic from jiangmiao's original code). That would let the function be defined for multiple different ways to delete text, but still handle pair deletion. I think the exact non-<BS> implementations are gonna have to be user config. The goal would be to allow this in the .vimrc:

inoremap <silent> <C-w> <C-R>=AutoPairsDelete("\<C-w>")<CR>

Though I'm not entirely sure if that can be a global map. Problem for later.

If you want to try implementing this, it shouldn't be too hard - it's mostly a matter of replacing the right instances of <BS> with an optional function parameter that defaults to <BS>. That should also mean none of the <BS> maps in the code or in the wild break.

If not, I'll implement it tomorrow. Out of capacity today unfortunately

[sodapopcan]

Hey, thanks for the response!

I think I'm ok with remapping, I can't imagine it being a problem! I'm a little confused, though, because even Vim says <c-h> and <bs> are interchangeable (see :h i_CTRL-H)! I thought maybe it's because I'm using Kitty but I tried in another terminal with the same result. On the other hand, you can't map <cr> without affecting <c-m> nor can you remap <tab> without also affecting <c-i> but my knowledge of how terminal codes work is, well, I really know any knowledge there! But again, happy to reamap.

Yes, <c-w> is word deletion for me which is provided through rsi.vim--I'm very much a "vim motions in normal mode, readline everywhere else kinda-person, including my OS and Vim's insert and command modes. This of course means I have to use another termkey though I don't use :term much as shell prompt anyway, usually just for opening temporary programs (like REPLs) that ++close on exit. I mostly stick to terminal splits for additional command prompts.

I certainly won't have time tonight or the next few days to implement but if you haven't gotten to it by the weekend I may give it a shot!

Thanks again!

[LunarWatcher]

I think I'm ok with remapping, I can't imagine it being a problem! I'm a little confused, though, because even Vim says and are interchangeable (see :h i_CTRL-H)! I thought maybe it's because I'm using Kitty but I tried in another terminal with the same result.

IIRC, it treats them the same internally, but they are still two different maps. Terminal code conversion is... complicated.

Yes, is word deletion for me which is provided through rsi.vim

Hm, that might add some complexity to the final map. Will have to look into that. Could've sworn <C-w> was a builtin, but /shrug

I checked. <C-W> is not overridden by rsi.vim, so it is using the builtin

[sodapopcan]

Terminal code conversion is... complicated.

This was all I knew about them before! 🙃

I checked. <C-W> is not overridden by rsi.vim, so it is using the builtin

D'oh, my bad. It's been so long that I never remember what's what (and never use other peoples' vims).

[LunarWatcher]

D'oh, my bad. It's been so long that I never remember what's what (and never use other peoples' vims).

All good, I lose track of what's built-in regularly myself :p

[LunarWatcher]

Closing this up, if you update the plugin, you should be able to add

inoremap <silent><expr> <C-w> autopairs#AutoPairsDelete("\<C-w>")

to your vimrc, and <C-w> should now be able to delete pairs in addition to words. There's tests for it (and I've tested it manually), but let me know if anything breaks