How to move around comments in any type of file?

Question

In $VIMRUNTIME/ftplugin/vim.vim, some mappings are installed to move the cursor to the previous/next comment:

" Move around comments
nnoremap <silent><buffer> ]" :call search('^\(\s*".*\n\)\@<!\(\s*"\)', "W")<CR>
vnoremap <silent><buffer> ]" :<C-U>exe "normal! gv"<Bar>call search('^\(\s*".*\n\)\@<!\(\s*"\)', "W")<CR>
nnoremap <silent><buffer> [" :call search('\%(^\s*".*\n\)\%(^\s*"\)\@!', "bW")<CR>
vnoremap <silent><buffer> [" :<C-U>exe "normal! gv"<Bar>call search('\%(^\s*".*\n\)\%(^\s*"\)\@!', "bW")<CR>

They use the key sequences [" and ]".

Are there similar mappings for other filetypes, or can we modify these mappings so that they work not only in Vim files but in other filetypes (shell, python, …)?

Answer 1

There are similar mappings for other filetypes.

1. For c-style block comments there exist built-in, ft-independent mappings [*/]* (and as a synonym [//]/)

/* 
This is the comment body.
Variation One.
*/

This type of block comment is used in many languages:

ActionScript, AutoHotkey, C, C++, C#, D, Go, Java, JavaScript, kotlin, Objective-C, PHP, PL/I, Rust, Scala, SASS, SQL, Swift, Visual Prolog, CSS

(https://en.wikipedia.org/wiki/Comparison_of_programming_languages_(syntax)#Block_comments)

2. Other mappings for certain filetypes in $VIMRUNTIME/ftplugin/ exist:

   • sql.vim [", ]" (same as vim.vim)
   • eiffel.vim [-, ]-
   • hamster.vim [#, ]# (overwrite built-in motions to jump to c-preprocessor #ifdef which are not used anyway in languages which do not have a c-preprocessor)

You can reuse them for languages with identical commentstrings by copying the code to ~/.vim/after/ftplugin/<language>.vim. (https://en.wikipedia.org/wiki/Comparison_of_programming_languages_(syntax)#Inline_comments)

For example, consider the language lua which has the same commentstring as eiffel:

1. :e $VIMRUNTIME/ftplugin/eiffel.vim
2. :45,91w ~/.vim/after/ftplugin/lua.vim
3. remove unneeded code and change g:no_eiffel_maps to g:no_lua_maps and you should get something like

if !exists("g:no_plugin_maps") && !exists("g:no_lua_maps")
  function! s:DoMotion(pattern, count, flags) abort
    normal! m'
    for i in range(a:count)
      call search(a:pattern, a:flags)
    endfor
  endfunction

  let comment_block_start = '^\%(\s\+--.*\n\)\@<!\s\+--'
  let comment_block_end = '^\s\+--.*\n\%(\s\+--\)\@!'

  nnoremap <silent> <buffer> ]- :<C-U>call <SID>DoMotion(comment_block_start, 1, 'W')<CR>
  xnoremap <silent> <buffer> ]- :<C-U>exe "normal! gv"<Bar>call <SID>DoMotion(comment_block_start, 1, 'W')<CR>
  nnoremap <silent> <buffer> [- :<C-U>call <SID>DoMotion(comment_block_end, 1, 'Wb')<CR>
  xnoremap <silent> <buffer> [- :<C-U>exe "normal! gv"<Bar>call <SID>DoMotion(comment_block_end, 1, 'Wb')<CR>

  let b:undo_ftplugin = b:undo_ftplugin .
    \ "| silent! execute 'unmap <buffer> [-' | silent! execute 'unmap <buffer> ]-'"
endif