How to differentiate quickfix window buffers and location list buffers?

Question

Recently I've been playing with my statusline and I'm coming to a point where I want to set a different highlighting group for the statusline of my quickfix window, location list window, and the other windows.

To do so I need to programmatically determine what type of buffer I am in. To differentiate between the "regular" buffers and the quickfix/location buffers I can easily test if &buftype returns quickfix.

The problem is to differentiate quickfix and location list since &buftype returns quickfix for both buffers.

I've seen this SO question which provides three solutions that don't satisfy me:

• The w:quickfix_title variable tells you what command was used to generate the list displayed in the window. This is not what I'm looking for since I can open my location list with different commands other than lopen (SyntasticCheck would be an example)
• Parsing the output of ls, matching the buffer number and checking if the name of the buffer matches Location List or Quickfix List. That could be a solution but I use different versions of Vim in different languages, so matching against all the possible names (e.g. Location List and Liste des emplacements) is not ideal.
• The third answer is about closing and reopening the windows to test if you were in one of them, this is really not convenient for a statusline setting.

So here are my two questions:

• Is there another way to easily differentiate the quickfix buffer from the location list one?
• If not what would be the best way to set a statusline background depending on the type of quickfix window you're in?

Answer 1

Ah ah. I've just implemented a function on the subject very recently: https://github.com/LucHermitte/lh-vim-lib/blob/master/autoload/lh/qf.vim#L125

If your version of Vim is recent enough, the discriminating information is stored in getwininfo()[some_winnr].loclist.

Otherwise, you'll have to execute :ls! and check whether you see "[Quickfix List]" or "[Locsomething List]" after the buffer number.

If you have i18n issues (does this means I've missed this problem because my vim flavours are much too recent?), again, in my library plugin, you'll find lh#po#context(...).translate(...) -- that won't work on Windows though :(