Passing the cursor position to edit_command_buffer

[rien333]

The alt+e bind to edit_command_buffer - that is, opening the current command in $EDITOR - is very handy. However, often I only realize half way editing a command that using my $EDITOR would be more convenient. In such cases, it's pretty cumbersome and superfluous to navigate to where I had my cursor in the fish shell, before I started my $EDITOR session.

Fortunately, editors like emacs (and maybe also vim) can be told to open a file at a specific line and column:

emacsclient --help
Usage: emacsclient [OPTIONS] FILE...
Tell the Emacs server to visit the specified files.
Every FILE can be either just a FILENAME or *[+LINE[:COLUMN]]* FILENAME.

Therefore, it would be great if edit_command_buffer could be told about the current cursor column (and possibly line). Afaik, there is currently no good way to pass such information to edit_command_buffer. I'm also not sure if it's possible to get the cursor's current column, and then pass that as some kind of argument to edit_command_buffer.

[zanchey]

So, there's commandline --cursor, which prints the offset from the origin of the line, which would work fine for the singe-line case. You could probably hack that into a lines/column thing in script, though my version is not terribly elegant:

function coord
    set -l offset (math (commandline --cursor ) + 1)
    set -l col 1
    set -l line 1
    set -l IFS
    set -l currpos 1
    set -l cmdline (commandline)
    while test $currpos -le $offset
        set -l curr (string sub --start $currpos --length 1 -- $cmdline)
        if test "$curr" = \n
            set line (math $line + 1)
            set col 0
        else
            set col (math $col + 1)
        end
        set currpos (math $currpos + 1)
    end
    echo $line:$col
end

Anyway, the output of the coord function can be passed along to emacsclient.

I don't think we're likely to change edit_command_buffer, because of the minimal support for the concept - happy to hear other ideas though.

[krobelus]

I think we can support passing the cursor position to some editors without breaking anyone. Most editors I can think of support some variation of +line:col file or file:line:col.

[rien333]

Certainly terminal editors (even nano, apparently).

[zanchey]

Switching on $EDITOR seems reasonable, though will probably have a lot of false negatives.

ee, joe and vim seem to only support line number, not column. At least for vim you can use a -c argument to move the cursor after starting.