Asking for advice for fully committing to leader key keybinds

Question

So, I recently tried switching my keybinds over to using the Leader key, which I've decided to make the space key, but that doesn't matter that much.

I've adapted to it pretty much instantly and I liked it much more than my old keybinds that were using the Alt key, but this really soon showed its problems: the Leader key, whatever it is set to, is a key that corresponds to a typable character.

Why's that a problem? While it isn't in stuff like my keybinds to switch buffers, for example, it is a problem if such a keybinding is used in order to toggle something that accepts inputting text, like the FTerm plugin, which allows you to run a terminal inside a floating window:

vim.api.nvim_set_keymap('n', '<leader>t', ':lua require("FTerm").toggle()<CR>', { noremap = true, silent = true })
vim.api.nvim_set_keymap('t', '<leader>t', '<C-\\><C-n>:lua require("FTerm").toggle()<CR>', { noremap = true, silent = true })

These sorts of keybinds aren't an issue if they're created with a modifier key since keybindings created like that don't result in something getting typed on the screen, but like this they create annoying edge cases like if you'd like to write some text that includes the Leader key in that terminal, it could actually turn on the keybind.

This isn't a technical problem. But since (N)Vim can't detect modifier key presses (being able to do stuff like :map <Alt>t action), and detecting only modifier key combinations (like :map <A-t> action), all Leader key keybindings are doomed to be normal mode-only keybinds. So, what I'm asking for is, how would you manage your keybindings for this, but still revolving around using the Leader key?

Answer 1

This does look like a bug in FTerm. As mentioned in the comments, usually in situations like this, normal mode mappings should not apply. This is usually achieved by setting the buftype to terminal. However, this is apparently not done in FTerm, resulting in the behaviour you describe. I would propose to open an issue asking the maintainers if it would be possible to change the buftype to terminal. In the meantime, a workaround like the one sketched below should work, as they seem to set the filetype to FTerm. (Note: The l:condition1 and the tnoremap line are just for for testing/illustration since I don't use FTerm. This also adds a mapping for <leader>xx in terminal mode and then never uses is, since in terminal mode the buftype is terminal).

Instead of directly mapping nnoremap <leader>xx 3j, you now have to remap using the WrapMapExpr function, which will fall back to the original characters of the mapping if one of the conditions specified at the top of the function are met.

function! WrapMapExpr(expr,keys)
    let l:condition1 = &buftype == "terminal"
    let l:condition2 = &filetype == "FTerm"
    if (l:condition1 || l:condition2)
        call feedkeys(a:keys, 'n')
        return ""
    else
        return a:expr
    endif
endfunction

nnoremap <expr> <leader>xx WrapMapExpr("3j", mapleader . "xx")
tnoremap <expr> <leader>xx WrapMapExpr("3j", mapleader . "xx")