`find_file` function for Emacs' vterm and fish shell

vterm.fish

function find_file
    set -q argv[1]; or set argv[1] "."
    vterm_cmd find-file (realpath "$argv")
end

function vterm_cmd --description 'Run an Emacs command among the ones been defined in vterm-eval-cmds.'
    set -l vterm_elisp ()
    for arg in $argv
        set -a vterm_elisp (printf '"%s" ' (string replace -a -r '([\\\\"])' '\\\\\\\\$1' $arg))
    end
    vterm_printf '51;E'(string join '' $vterm_elisp)
end

function vterm_printf
    if begin; [  -n "$TMUX" ]  ; and  string match -q -r "screen|tmux" "$TERM"; end 
        # tell tmux to pass the escape sequences through
        printf "\ePtmux;\e\e]%s\007\e\\" "$argv"
    else if string match -q -- "screen*" "$TERM"
        # GNU screen (screen, screen-256color, screen-256color-bce)
        printf "\eP\e]%s\007\e\\" "$argv"
    else
        printf "\e]%s\e\\" "$argv"
    end
end