neovim/modules/nvim-tree-lua.nix

{ nix2lua, vim, ... }:

{ configs ? { }
, keymaps ? [
    { mode = "n"; bind = "<leader>nt"; command = "<CMD>NvimTreeToggle<CR>"; }
    { mode = "n"; bind = "<leader>nf"; command = "<CMD>NvimTreeFindFile<CR>"; }
  ]
}:

with nix2lua.lib;
let isEmptyVar = name: eq "" (var name); in
{
  nvim-web-devicons = true;

  nvim-tree-lua = (
    [
      (pipe1 (require "nvim-tree") (call "setup" configs))

      (local (func "open_nvim_tree" [ "data" ] [
        # buffer is a [No Name]
        (local (set "isNoNameBuffer"
          (and
            (isEmptyVar "data.file")
            (isEmptyVar "vim.bo[data.buf].buftype")
          )
        ))

        # buffer is a directory
        (local (set "isDirectory"
          (eq 1 (vim.fn.isdirectory "data.file"))
        ))

        (if' (not (and (var "isNoNameBuffer") (var "isDirectory")))
          return_void
        )

        # change to the directory
        (if' (var "isDirectory")
          (vim.cmd.cd "data.file")
        )

        # open the tree
        (pipe1 (require "nvim-tree.api") (call0 "tree.open"))
      ]))

      (vim.api.nvim_create_autocmd [ "VimEnter" ] { callback = var "open_nvim_tree"; })
    ]
    ++ (map vim.keymap.set keymaps)
  );
}