Question

I really like this vim trick to use the left and right arrows to flip between buffers:

"left/right arrows to switch buffers in normal mode
map <right> :bn<cr>
map <left> :bp<cr>

(Put that in ~/.vimrc)

But sometimes I’m munching on a sandwich or something when scrolling around a file and I really want the arrow keys to work normally.
I think what would make most sense is for the arrow keys to have the above buffer-flipping functionality only if there are actually multiple buffers open.

Is there a way to extend the above to accomplish that?

Answer 1

I’d rather have a completely different mapping because:

• cursors are really useful, and not having them because you have a hidden buffer will annoy you a lot
• some plugins use <left> and <right> because they are less obfuscated than l and h; those plugins are likely to break with such mappings

Anyway, you can try this:

nnoremap <expr> <right> (len(filter(range(0, bufnr('$')), 'buflisted(v:val)')) > 1 ? ":bn\<cr>" : "\<right>")
nnoremap <expr> <left> (len(filter(range(0, bufnr('$')), 'buflisted(v:val)')) > 1 ? ":bp\<cr>" : "\<left>")

To see documentation on the pieces above:

:h :map-<expr>
:h len()
:h filter()
:h range()
:h bufnr()
:h buflisted()