How to diff two lines in an open file in vim? - vim

I occasionally see very long lines in my code that I need to check if they are the same. Is there a way in vim to select two lines and diff them to show any differences between the two?
For example, given the two lines in vim:
AVeryLongReturnType* MyLongClassName:hasAnEvenLongerFunction(That *is, Overloaded *with, Multiple *different, Parameter *lists);
AVeryLongReturnType* MyLongClassName:hasAnEvenLongerFunction(That *is, Overloaded *with, Multiple *different, Parameter *1ists);
I would like vim to tell me that the two lines are in fact different because each spells "lists" differently. Is this possible, and if so, how do I do it?

A quick and dirty solution is to just select both lines and sort them while removing duplicates:
select lines
":sort u"
if only one line remains, both were equal
if both remain, there most be some difference
An undo recovers everything again.

An alternative to #sehe's approach would not require the use of temp files:
funct! DiffTwoTexts(text1, text2)
new
put =a:text1
normal ggdd
diffthis
new
put =a:text2
normal ggdd
diffthis
endfunct
funct! DiffTwoLines(line1, line2)
let text1 = getline(a:line1)
let text2 = getline(a:line2)
call DiffTwoTexts(text1, text2)
endfunct
comma! DiffWithNext call DiffTwoLines('.', line('.') + 1)
This will still be pretty hard to read, since it keeps everything on a single line, so I came up with this modification:
funct! EvalTextPreprocessor(expr, text)
let text = a:text
return eval(a:expr)
endfunct
comma! -nargs=1 DiffWithNextPre call DiffTwoTexts(
\ EvalTextPreprocessor(<q-args>, getline('.')),
\ EvalTextPreprocessor(<q-args>, getline(line('.') + 1)))
This new command takes a vimscript expression as its argument, wherein the variable text refers to whichever line is being preprocessed. So you can call, e.g.
DiffWithNextPre split(text, '[(,)]\zs')
For your sample data, this gives the two buffers
AVeryLongReturnType* MyLongClassName:hasAnEvenLongerFunction(
That *is,
Overloaded *with,
Multiple *different,
Parameter *lists)
;
and
AVeryLongReturnType* MyLongClassName:hasAnEvenLongerFunction(
That *is,
Overloaded *with,
Multiple *different,
Parameter *1ists)
;
Only the lines that start with Parameter are highlighted.
You can even build up from there, creating a command
comma! DiffTwoCFunctionSigs DiffWithNextPre split(text, '[(,)]\s*\zs')
Notice that I modified the regexp a bit so that it will keep trailing spaces at the end of lines. You could get it to ignore them entirely by moving the \s* to after the \zs. See :help /\zs if you're unfamiliar with what that vim-specific RE atom does.
A nicety would be to make the command take a range (see :help command-range), which you could use by diffing the first line of the range with the last line. So then you just visual-select from the first line to the second and call the command.

I used linediff.vim.
This plugin provides a simple command, ":Linediff", which is used to diff two separate blocks of text.

That is not a feature, however it is easily scripted, e.g. in your vimrc:
function! DiffLineWithNext()
let f1=tempname()
let f2=tempname()
exec ".write " . f1
exec ".+1write " . f2
exec "tabedit " . f1
exec "vert diffsplit " . f2
endfunction
This will open the current and next lines in vertical split in another tab.
Note that this code is a sample
it doesn't check whether next line exists (there are any following lines)
it doesn't cleanup the tempfiles created
a nice improvement would be to take a range, or use the '' mark to select the other line
You can leave off the 'vert' in order to have a horizontal split
Map it to something fancy so you don't have to :call it manually:
:nnoremap <F10> :call DiffLineWithNext()^M

you could also just create a new empty window buffer and copy line, then make command:
:windo diffthis
this should open a new window showing the differences of those 2 lines

Related

How do I re-select a range in vim? [duplicate]

Is it possible to reuse the range of ex commands in VIM?
As an example, I can write (copy) lines 4 to 10 from my current file to a new file using the following command:
:4,10w foo/bar.txt
But what I really want to do is move the lines to a new file. I can do this like so:
:4,10w foo/bar.txt
:4,10d
But it's a bit annoying to have to type 4,10 both times.
So I have two questions:
Generally, Is there a way to reference the previously used range in ex commands?
Specifically, if there is not a way to do (1), is there any easier way to cut and paste a number of lines from one file into a new one.
I usually use cat to do this:
:4,10!cat > foo/bar.txt
This works because you're piping the lines through cat and replacing them with the resulting output, which is nothing. And of course you can append to the end of an existing file by doing >> instead of >.
I am unaware of an answer to (1), but to answer (2), there are a number of different ways of doing it that don't require reselecting the lines by hand. In visual mode this will work:
4GV10G
:w foo/bar.txt
gvd
because gv reselects the previous selection, which is almost what you want, without using an ex range.
But you could just turn the problem on its head, and try:
:4,10d
:sp foo/bar.txt
pZZ
to cut, then paste into a new file, then close it.
Other than using the Vim history (:Cursor Up, q:) and removing the previous command so that just the range is kept, there's no way to re-use the last range, no magic variable.
If I used this move lines combination more often, I would write a custom command for it:
command! -bang -range -nargs=1 -complete=file MoveWrite <line1>,<line2>write<bang> <args> | <line1>,<line2>delete _
You need to specify the range only once and save typing.
You can write something like this for other combinations, too. The main challenge is specifying all the command attributes (bang, range, completion), and, later, remembering the custom command name.
Generally, what I do is delete the lines from the one file, switch to the other file, and paste.
Also, I generally use marks. Instead of typing the actual numbers, I hit mb to mark the beginning line, then go to the end line and hit d'b to delete back to the line marked as b. But you can use mb to mark a begin line, and me to mark an end line, then run an ex command:
:'b,'e w somefile.txt<Enter>
Of course you can use any letters from a through z for your marks; I usually use b and e but you can use what you like.
How I would move the lines:
m'b
<navigate to end line>
d'b
:n somefile.txt<Enter>
p
Ctrl+^
Ctrl+^ switches from the current open file to the previous open file. (You could also just open a pane and switch panes, if you prefer. Panes don't work in plain vi but do work in vim.)
The above assumes that you have set the autowrite option on. With autowrite, the :n command and Ctrl+^ both just write the current file and then switch files, instead of complaining that the file has been changed without you saving it. You can also do the above and just explicitly write the file before using :n or Ctrl+^.
By the way, I use Ctrl+^ so much that I mapped it onto K. Easier to type, but I got in that habit long ago when I used to have to sometimes use a dumb terminal that couldn't type Ctrl+^.
By the way, when you delete lines, they go into the "unnamed buffer". In vim, the unnamed buffer is preserved when you switch files. In original vi, the unnamed buffer is cleared. So the above won't work with old vi. You can make it work by deleting into a named buffer, then pasting from the named buffer; that works in any version of vi.
m'b
<navigate to end line>
"ad'b
:n somefile.txt<Enter>
"ap
Ctrl+^
The above deletes into the buffer named a, then pastes from a in the other file. This does work in vim of course; it's just that you don't need it.
Here's a command-line mapping that achieves this. I've bound it to CTRL-G CTRL-U, since it performs a similar action as CTRL-U. (But you can change that, of course!)
" c_CTRL-G_CTRL-U Remove all characters between the cursor position and
" the closest previous |:range| given to a command. When
" directly after a range, remove it.
" Useful to repeat a recalled command line with the same
" range, but a different command.
let s:singleRangeExpr = '\%(\d\+\|[.$%]\|''\S\|\\[/?&]\|/[^/]*/\|?[^?]*?\)\%([+-]\d*\)\?'
let s:rangeExpr = s:singleRangeExpr.'\%([,;]'.s:singleRangeExpr.'\)\?'
let s:upToRangeExpr = '^\%(.*\\\#<!|\)\?\s*' . s:rangeExpr . '\ze\s*\h'
" Note: I didn't take over the handling of command prefixes (:verbose, :silent,
" etc.) to avoid making this overly complex.
function! s:RemoveAllButRange()
let l:cmdlineBeforeCursor = strpart(getcmdline(), 0, getcmdpos() - 1)
let l:cmdlineAfterCursor = strpart(getcmdline(), getcmdpos() - 1)
let l:upToRange = matchstr(l:cmdlineBeforeCursor, s:upToRangeExpr)
if empty(l:upToRange)
return getcmdline()
else
call setcmdpos(strlen(l:upToRange) + 1)
return l:upToRange . l:cmdlineAfterCursor
endif
endfunction
cnoremap <C-g><C-u> <C-\>e(<SID>RemoveAllButRange())<CR>
as a plugin
My CmdlineSpecialEdits plugin has (among many others) this mapping as well.
You can also do something like this to write the contents of the anonymous register to file2.txt
:4,10d | :call writefile(split(##, "\n", 1), 'file2.txt')
You can do the deleting first, and then open a new tab and paste the contents - so :4,10d, then :tabe foo/bar.txt, followed by p... does that sound better?
In Vim 8 and NVIM 0.3.7 as of writing, you can actually edit your command list and hit enter to execute.
:4,10w foo/bar.txt
q:
q: is to enter interactive ex command
Once you open the interactive command list, you can then edit it and press enter to execute.
I love moopet's answer though, it's efficient.

copying just specific lines in a file with vim

Could someone please tell me know how to copy specific lines, for example
Lines 10-20, 22, 24-30 in a file, so I can paste it to another file?
I saw this stackoverflow post as someone had pointed out, however, I'm asking a different questionwhere
Here's a fun little idea. Paste this in your ~/.vimrc:
command! -nargs=* Y :call YankList(<f-args>)
fun! YankList(...)
let yanklist = []
for i in a:000
if match(i, "-") != -1
let split = split(i, "-")
let yanklist = yanklist + range(split[0], split[1])
else
let yanklist = yanklist + i
endif
endfor
call setreg('"', "")
for i in yanklist
call setreg('"', getline(i), "al")
endfor
endfun
Now you can specify lines to yank to the unnamed register. So do:
:Y 10-20 22 24-30
and use p to paste them wherever you want them. (inclusive)
I'd like to edit this post even though it's old to suggest the more "vimmy" way of doing this. See :help usr_10 | 131.
You could do:
10GV20G"ay
22G"AY
24GV30G"Ay
G"ap
Also, if there were some specific pattern that each of these lines contained, then you could grab them by said pattern. Say for example I wanted to yank all lines containing the word "foo", then I could do
:g/foo/y "
Here is a simple solution using Registers.
Using your scenario you provided, needing to yank Lines 10-20, 22, 24-30
Just yank each group with "A".
:10,20y A
:22y A
:24,30y A
At this point you have each of those sets of lines copied to your "A" register. Now you you can use p to paste as you normally would OR you can use "Ap (double quote, Letter of Register, then p to paste just those you yanked with to the A Register.
Read more about Registers Here and Here
Use visual mode, or directly:
:10,20yank
Copy to a new file:
:new | put | 0d
Usually, you'll either have a criterion, e.g. move all lines containing pattern to the end:
:g/pattern/m$
To copy (:copy or :t)
:g/pattern/t$
To yank to a register:
:let #a="" | g/pattern/y A
Now, you can use it wherever you like e.g. "aP to paste it.
If you don't have patterns like that to use, just use text motions, e.g. }:y A to append a block of lines till the next empty line to register a etc.
Edit PS. I thought I'd explain a bit more why I mention m$ to move to the end (a personal favourite of mine):
If you opt to move/copy lines to the end of the file (m$), you can then write them to another file at once. E.g.
:$mark a
:g/pattern/t$
:'a,$w newfile.txt
Copies the lines matching to file newfile.txt. Now delete the copy from the source file:
:'a,$d
Have the both files open - invoke directly from the command line as vim fileone filetwo or open vim and then :e file. You can then switch between them with buffer commands, for two files :bn and :bp are equivalent (buffer next, previous). Then just copy the lines.
This can be done pretty easily: 10G to go to line 10, y10y to copy the next ten lines, then :bn and p to stick it in the other file.

Reusing the previous range in ex commands in VIM

Is it possible to reuse the range of ex commands in VIM?
As an example, I can write (copy) lines 4 to 10 from my current file to a new file using the following command:
:4,10w foo/bar.txt
But what I really want to do is move the lines to a new file. I can do this like so:
:4,10w foo/bar.txt
:4,10d
But it's a bit annoying to have to type 4,10 both times.
So I have two questions:
Generally, Is there a way to reference the previously used range in ex commands?
Specifically, if there is not a way to do (1), is there any easier way to cut and paste a number of lines from one file into a new one.
I usually use cat to do this:
:4,10!cat > foo/bar.txt
This works because you're piping the lines through cat and replacing them with the resulting output, which is nothing. And of course you can append to the end of an existing file by doing >> instead of >.
I am unaware of an answer to (1), but to answer (2), there are a number of different ways of doing it that don't require reselecting the lines by hand. In visual mode this will work:
4GV10G
:w foo/bar.txt
gvd
because gv reselects the previous selection, which is almost what you want, without using an ex range.
But you could just turn the problem on its head, and try:
:4,10d
:sp foo/bar.txt
pZZ
to cut, then paste into a new file, then close it.
Other than using the Vim history (:Cursor Up, q:) and removing the previous command so that just the range is kept, there's no way to re-use the last range, no magic variable.
If I used this move lines combination more often, I would write a custom command for it:
command! -bang -range -nargs=1 -complete=file MoveWrite <line1>,<line2>write<bang> <args> | <line1>,<line2>delete _
You need to specify the range only once and save typing.
You can write something like this for other combinations, too. The main challenge is specifying all the command attributes (bang, range, completion), and, later, remembering the custom command name.
Generally, what I do is delete the lines from the one file, switch to the other file, and paste.
Also, I generally use marks. Instead of typing the actual numbers, I hit mb to mark the beginning line, then go to the end line and hit d'b to delete back to the line marked as b. But you can use mb to mark a begin line, and me to mark an end line, then run an ex command:
:'b,'e w somefile.txt<Enter>
Of course you can use any letters from a through z for your marks; I usually use b and e but you can use what you like.
How I would move the lines:
m'b
<navigate to end line>
d'b
:n somefile.txt<Enter>
p
Ctrl+^
Ctrl+^ switches from the current open file to the previous open file. (You could also just open a pane and switch panes, if you prefer. Panes don't work in plain vi but do work in vim.)
The above assumes that you have set the autowrite option on. With autowrite, the :n command and Ctrl+^ both just write the current file and then switch files, instead of complaining that the file has been changed without you saving it. You can also do the above and just explicitly write the file before using :n or Ctrl+^.
By the way, I use Ctrl+^ so much that I mapped it onto K. Easier to type, but I got in that habit long ago when I used to have to sometimes use a dumb terminal that couldn't type Ctrl+^.
By the way, when you delete lines, they go into the "unnamed buffer". In vim, the unnamed buffer is preserved when you switch files. In original vi, the unnamed buffer is cleared. So the above won't work with old vi. You can make it work by deleting into a named buffer, then pasting from the named buffer; that works in any version of vi.
m'b
<navigate to end line>
"ad'b
:n somefile.txt<Enter>
"ap
Ctrl+^
The above deletes into the buffer named a, then pastes from a in the other file. This does work in vim of course; it's just that you don't need it.
Here's a command-line mapping that achieves this. I've bound it to CTRL-G CTRL-U, since it performs a similar action as CTRL-U. (But you can change that, of course!)
" c_CTRL-G_CTRL-U Remove all characters between the cursor position and
" the closest previous |:range| given to a command. When
" directly after a range, remove it.
" Useful to repeat a recalled command line with the same
" range, but a different command.
let s:singleRangeExpr = '\%(\d\+\|[.$%]\|''\S\|\\[/?&]\|/[^/]*/\|?[^?]*?\)\%([+-]\d*\)\?'
let s:rangeExpr = s:singleRangeExpr.'\%([,;]'.s:singleRangeExpr.'\)\?'
let s:upToRangeExpr = '^\%(.*\\\#<!|\)\?\s*' . s:rangeExpr . '\ze\s*\h'
" Note: I didn't take over the handling of command prefixes (:verbose, :silent,
" etc.) to avoid making this overly complex.
function! s:RemoveAllButRange()
let l:cmdlineBeforeCursor = strpart(getcmdline(), 0, getcmdpos() - 1)
let l:cmdlineAfterCursor = strpart(getcmdline(), getcmdpos() - 1)
let l:upToRange = matchstr(l:cmdlineBeforeCursor, s:upToRangeExpr)
if empty(l:upToRange)
return getcmdline()
else
call setcmdpos(strlen(l:upToRange) + 1)
return l:upToRange . l:cmdlineAfterCursor
endif
endfunction
cnoremap <C-g><C-u> <C-\>e(<SID>RemoveAllButRange())<CR>
as a plugin
My CmdlineSpecialEdits plugin has (among many others) this mapping as well.
You can also do something like this to write the contents of the anonymous register to file2.txt
:4,10d | :call writefile(split(##, "\n", 1), 'file2.txt')
You can do the deleting first, and then open a new tab and paste the contents - so :4,10d, then :tabe foo/bar.txt, followed by p... does that sound better?
In Vim 8 and NVIM 0.3.7 as of writing, you can actually edit your command list and hit enter to execute.
:4,10w foo/bar.txt
q:
q: is to enter interactive ex command
Once you open the interactive command list, you can then edit it and press enter to execute.
I love moopet's answer though, it's efficient.

Using Vim, isn't there a more efficient way to format LaTeX paragraphs according to this best practice?

The best practice mentioned in the title is the one suggested by Uri:
When writing paragraphs, start each
sentence at the beginning of a line,
and if it spills over, each subsequent
line is tabbed.
I use gVim with Vim-LaTeX, which comes with an indent/tex.vim file, to edit LaTeX files. The way I currently implement the practice mentioned above is as follows:
I :set textwidth=79 to automatically break lines before they become too long.
I manually hit Enter after I finish inserting each sentence.
If I'm done with revising and editing a sentence, I manually shift any spillovers using >>, prefixing it with a count if necessary.
Occasionally, that last step will make one or more spillovers go over the maximum line width. In this case, I
gqq the faulty line.
J my way through to the end of the sentence.
repeat steps 1 and 2 as necessary.
As you can imagine, this can become tedious. Isn't there a more efficient way to achieve the same result? Ultimately, I want to be able to write the sentences without worrying about their format, and then use gqap, or gqip, to automatically produce the result that I currently produce manually.
To do that, I suspect that I will need to write a formatexpr of my own, but I'm not sure how to proceed. I have found a number of plugins, Latex Text Formatter and Text (Especially LaTeX) Formatter, and a tip, but none of them seem to suit my needs, and I'm not sure how to modify them to do so.
I may well be oversimplifying the problem, but does this mapping do what you want?
nnoremap \z (j>>gq)
So pressing \z in normal mode will do the following: From the cursor position, jump to the start of the sentence. Then go to the next line and indent it. Then reformat from this line to the end of the sentence. Reformatting sentence-wise is the way to go, rather than reformatting each line individually, as your method seems to do.
Of course you can use an insert-mode mapping if you prefer, or even try redefining the behaviour of the Enter key to do this automatically (although I don't know if this will have unintended consequences...).
One way to do this is not by actually breaking the lines in the file but instead doing the following:
set wrap linebreak
let &showbreak='===> '
The wrap option makes long lines wrap instead of extending off the screen and linebreak makes the line breaks happen only at characters specified in the breakat option.
You can set showbreak to anything that is pleasing to your eye. My favorite when I'm using vim where unicode characters work right is:
let &showbreak="\u21aa "
This puts a ↪ symbol at the beginning of each wrapped line.
I also like to turn on line numbers (set number) to give another indicator of what the actual lines in the file are.
To make navigating the file easier you might want to use
noremap j gj
noremap k gk
noremap gj j
noremap gk k
This makes k and j move up and down by displayed lines not file lines. To affect the cursor keys as well replace k with <Up> and j with <Down>.
One option that takes different tack than tabbing subsequent lines would be to set the w flag in formatoptions. When you do that it changes the way Vim identifies new paragraphs, and lines ending in a space are understood to continue on a new line as part of same paragraph. See :h fo-table.
If you set the w flag and enter your text so that continued sentence lines are the only ones ending in a space (and abandon completely practice of entering tabs at beginning of any text lines) then I think you should be able to use gqap to format text paragraphs as you want. To get visual cues to logical structure you can then set listchars to display the eol (i.e., <cr>) character and set different highlightings for <space><cr> and for <non-space><cr> so that sentence/paragraph ends are easily spotted.
Another benefit of this method is that you can just type your text naturally and let line breaks be entered automatically by textwidth setting. (Just make sure that LaTeX formatting lines don't break automatically in textwidth area; you want them to have non-space char as last char in line.)
That tip also caught my eye. Here's how I solved the problem (a diff of the changed lines in tex.vim):
*** tex.vim.old 2011-08-16 08:26:56.845046457 +0200
--- tex.vim 2011-08-16 08:59:14.736306930 +0200
***************
*** 90,95 ****
--- 90,96 ----
" LH modification : \begin does not always start a line
if line =~ '\\begin{\(.*\)}' && line !~ 'verbatim'
\ && line !~ 'document'
+ \ || line =~ '^\s*[A-Z].*[a-zA-Z0-9,]\s*$\C'
let ind = ind + &sw
***************
*** 105,110 ****
--- 106,112 ----
" Subtract a 'shiftwidth' when an environment ends
if cline =~ '^\s*\\end' && cline !~ 'verbatim'
\&& cline !~ 'document'
+ \|| line =~ '\.\s*$'
if g:tex_indent_items == 1
" Remove another sw for item-environments
Basically it indents new lines when the previous line starts with a capital letter and ends with a letter, digit, or comma, and "unindents" new lines with the previous line ends with a period.
There is definitely room for improvement (better criteria) but for me it works all right so far.
I find the suggestion from #kev (and the people commented) at this post to be the most satisfying.
There, it is explained that by setting
:set fo+=n
followed by either
:let &flp='^\s*\\(item\|end\|begin)*\s*'
or
:let &l:flp='^\s*\\\(item\|end\|begin\)\s*'
lets you type gggqG to reformat the entire file.
I use the vim-textobj-usr plugin to define a "LaTeXPar" text-object. Then I can use gwal to format.
There is already a vim-textobj-latex plugin, but the biggest text-object it defines is "environment". This is not what I (and OP) want.
A "LaTeXPar" is delimited by
an empty line
a line begin with \[, \], \begin, \end, }
a line end with {
this is adapted to my writing habit: I always have an empty line after \section, always use \[ \] on a single line, and so on. You can easily write one for yourself.
Here is the relative part in my ~/.vim/ftplugin/tex.vim.
call textobj#user#plugin('latexpar', {
\ 'par': {
\ 'select-a-function': 'LaTeXPar',
\ 'select-a': 'al',
\ },
\ })
function! LaTeXPar()
let pattern='\v^$|^\s*(\\\[|\\\]|\\begin|\\end|\})|\{$'
if search(pattern,"bW")
normal! j
else
normal! gg
endif
let head_pos = getpos('.')
if search(pattern,"W")
normal! k
else
normal! G
endif
let tail_pos = getpos('.')
" echo head_pos[2]
" echo tail_pos[2]
return ["V", head_pos, tail_pos]
endfunction

Vim: Split Words Into Lines?

I frequently use Shift+J in visual mode to join several selected lines into a single line with the original lines separated by spaces. But I am wondering if there is an opposite shortcut such that it will split selected words into separate lines (one word per line).
Of course I can do:
:'<,'>s/ /^M/g
But something more succinct in terms of keystrokes would be very useful. Has anyone else found a way to do this?
Thanks in advance,
-aj
Map it if you are using it often in your ~/.vimrc file or similar
vnoremap \ll :'<,'>s/ /^M/g<cr>
nnoremap \ll :s/ /^M/g<cr>
if you are only wanting to to it multiple times now you can use & command to repeat last search also
Theres also gqq but thats for textwidth eg 80 chars
Recently I stumbled across the same problem. My solution is the following vim function (put in my .vimrc):
function SplitToLines() range
for lnum in range(a:lastline, a:firstline, -1)
let words = split(getline(lnum))
execute lnum . "delete"
call append(lnum-1, words)
endfor
endfunction
This can be used with line ranges, e.g., as follows
:26call SplitToLines()
which would split line number 26. But the code also handles ranges of lines gracefully (that's why the range in the for loop is built in reverse order).
1,10call SplitToLines()
will split lines 1 to 10 into several lines. However, I mostly use this in visual mode, like
'<,'>call SplitToLines()
which splits all lines that are visually marked. Of course you may define some single letter abbreviation for this function call (with auto completion by Tab I do not find it necessary). Also note that by adding an additional argument which would also be used by 'split' you can have a function that does split lines at specific patterns (instead of just white space).
I use this in my config to Un-Join/split the last word on current line:
nnoremap <C-J> g_F<Space><Space>i<CR><Esc>k
It maps CTRL-j to do the opposite of Join, I think of it as Counter-Join :) I mostly use it to convert between K&R style vs ...the other kind of curly brace placement.
g_ : search for the last non-whitespace on current line
F<Space> : reverse-find first space
<Space> : go one character forward
i : enter insert mode
<CR> : insert a line break
<Esc> : return to normal mode
k : go up one line to where we begun

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