Break long comments

Question

Given the file alfa.c:

// Lorem ipsum dolor sit amet, apeirian constituam interpretaris no his, soluta salutandi persequeris vel ne, facete impedit contentiones te eam. Ut utamur habemus qualisque usu
#include <stdio.h>
int main() {
  puts("hello world");
}

I would like to format all long comments to get results like this:

// Lorem ipsum dolor sit amet, apeirian constituam interpretaris no his, soluta salutandi
// persequeris vel ne, facete impedit contentiones te eam. Ut utamur habemus qualisque usu
#include <stdio.h>
int main() {
  puts("hello world");
}

I see Vim has an option to format comments, however I did not see any Ex mode commands. Is this possible?

Answer 1

Depending on your configuration you can achieve the desired result with:

gq

If you want to use this as a ex command you can use:

normal! gqq

to format the current line.

Aslo, it's worth adding the flags a and c to your 'formatoption' configuration:

set fo+=ac

This will try to preserve the current comment formatting as well as automatically formatting the paragraph.

You may want to have a look at:

• :h format
• :h gq
• :h fo-table
• :h 'fo'

Answer 2

You can set a limit for a line, like 80 columns for a line.

Then you can set a autocommand to split such lines whenever you save the file.

:au BufWrite *.* :%s#^\s\*//.\{78\}#&\r//#g

Put this in your ~/.vimrc.