ALE Fix for a visual selection

Question

I am figuring out a way to apply linting to a visual selection of code. For example:

I only want to lint run :ALEFix on that section of code, and not the 100s (or 1000s) of lines of other code in the file. My first thought was doing something like:

• Copy the visual selection. y
• Option a new file and paste that in. :vs tmp
• Run :AleFix on that shortened file.
• Copy-all: ggVG"*y
• Close that file :q!
• Do gv to re-highlight the visual selection at the start.
• Paste in the copy-buffer p

What might be a better way to do that? And if the above seems like it might be the best way, what might be a clean function to do that with? (I'll try writing one myself as well...)

Answer 1

You can use Vim's built-in :h formatprg and :h gq for this.

You can set formatprg option to the fixer/formatter tool of choice, like:

:let &l:formatprg='some-program --some-flag'

Or with set syntax which requires escaping spaces:

:setlocal formatprg=some-program\ --some-flag

You may persist this setting in your vimrc, like:

augroup RangeFixer
  autocmd!
  autocmd FileType python let &l:formatprg='some-program --some-flag'
augroup END

Or persist it in the appropriate ftplugin file (e.g. ~/.vim/ftplugin/python.vim or ~/.vim/after/ftplugin/python.vim), which removes the need for autocmds:

" ~/.vim/after/ftplugin/python.vim

let &l:formatprg='some-program --some-flag'

Once you have configured formatprg using one of above, then you can highlight the range you want to format, then press gq.

Answer 2

A little rough around the edges, but here is what I came up with (which I've tested and works for me):

function _AleVisualSelection()
    normal! gvy
    vs tmp
    normal!p
    ALEFix black
    normal! ggVG
    sleep 300m
endfunc

vnoremap    0   <Esc>:call _AleVisualSelection()<CR>y:q!<CR>gvp