Kakoune: Add vim-surround-like feature

[opsound]

Since selections are so integral to Kakoune, it would be awesome to have a feature for surrounding the selection(s), and changing the surrounding characters.

See https://github.com/tpope/vim-surround

[lenormf]

This is pretty easy to do by default already, using i and a. If you want to make things easier, you could implement a script that declares some bindings to quickly surround a selection, but I don't think this would be a good fit for upstream.

[spinningarrow]

@lenormf could you elaborate how to change the surrounding characters using i and a? I'm pretty new to Kakoune and I had the same question as OP.

[lenormf]

Assuming you want to surround the word under the cursor with a shell variable expansion:

<a-i>w
i ${ <esc>
a } <esc>

i inserts things at the beginning of the selection, a extend the selection by its end.

[spinningarrow]

I see. Is there also a way to do the second thing i.e. changing the surrounding characters? For example if I have

"something quoted"

I'd like to change the double quotes to single quotes to make it

'something quoted'

As an aside, I'm fine with this being in a separate script but it's such a useful and well-used feature that I would second it being considered to be in core. This would make it different from vim though, where it is an external plugin.

[spinningarrow]

I think I figured out the answer to my question above. I can do this by selecting around the quotes (alt+a ") then splitting to multiple cursors on the quote (s") and then changing them to single quotes (c').

[lenormf]

r' would keep you in normal mode, but c' works as well.

[opsound]

Thanks for the tips, all. I need more practice using the kakoune way. It would be great for more experienced users to share some of these usage patterns in the wiki :)

[ianthehenry]

In case future generations find this, you can add this to your kakrc to get behavior very similar to vim-surround:

def surround %!on-key %@exec %sh&
  case "$kak_key" in
  "<lt>") key="<" ;;
  "<gt>") key=">" ;;
  "<space>") key=" " ;;
  "<tab>") key="\t" ;;
  \<*\>) echo ":echo<space>no<ret>"; exit 1 ;;
  *) key="$kak_key" ;;
  esac

  open="$key"
  close="$key"
  case "$key" in
  ")") open="(" ;;
  "]") open="[" ;;
  "}") open="{" ;;
  ">") open="<" ;;
  "(") open="( "; close=" )" ;;
  "[") open="[ "; close=" ]" ;;
  "{") open="{ "; close=" }" ;;
  "<") open="< "; close=" >" ;;
  esac

  epilogue=${close//?/H}

  open=${open/</<lt>}
  close=${close/>/<gt>}

  open=${open/ /<space>}
  close=${close/ /<space>}

  echo "i$open<esc>a$close<esc>$epilogue"
&@!

map global user s ":surround<ret>"

Now you can use, e.g. ,s) to surround the selection with matching parens, or ,s* to surround with asterisks.

(Improvements welcome -- the odd nested string quoting is particularly painful.)

[Delapouite]

Great, thanks ianthehenry. I have added your snippet to the wiki : https://github.com/mawww/kakoune/wiki/Surround-selections . This way it can be tweak easily by anyone.

[alexherbo2]

I added this feature in #1295.