Directory mode jump

[jsparkes]

This parallels the dired-jump command found in emacs dired-x. Using C-x C-j in a file opens the directory that contains the file in directory-mode. If used in a directory-mode buffer, the it moves up to the parent directory, like ^ in directory-mode.

I have this command hard-wired into my brain, and miss it in lem.

If this is not acceptable, I have an alternate change that exports directory-mode and directory-mode-up-directory so that I can implement it in my init file.

[vindarel]

Hi, there is already a command on C-x C-j that mimics Dired (open the directory of the current file, place the cursor on the file name).

Using C-x C-j in a file opens the directory that contains the file in directory-mode

so it seems this feature is already baked in, but better, because you only call (find-file (buffer-directory) when find-file-directory does a bit more (move the cursor, more checks). You don't re-use the existing function.

If used in a directory-mode buffer, the it moves up to the parent directory, like ^ in directory-mode.

looks like this is the only addition you want. Why not do it in the existing command?

So, I am personally not happy with your PR because I use C-x C-j and you rebind it to another command, this introduces a breaking change.

[jsparkes]

I've made the change to update find-file-directory only. The directory up command should also select and recenter, but I couldn't make it work easily.

[jsparkes]

It took an hour, but I now have the directory up command selecting the previous directory name similar to how it was done for find-file-directory. I hope the code isn't too ugly.

[vindarel]

nice, this LGTM thanks.

(maybe the concatenate and split-sequence could be terser by using str:concat and str:split, a minor point)

You can add cxxxr as a reviewer.

[cxxxr]

I think it's good.
Thank you.