How to optimise my script, a script for opening new a new emacs instance only if no instance is present

Question

I use emacs and I have written a script which is half in bash and half in AppleScript in order to do the following (first I write the code and then the pseudocode). We assume that a emacs daemon is running.

pseudocode:

if (no emacs GUI process is active or a process is active but no window is present)
then 
    open a new emacs window using emacsclient 
    and 
    put that window in foreground
else
    open the app Emacs.app (so no new instance is created and we simply put 
                            the focus on the existing emacs window)

code for "switchToEmacs.sh"

#!/bin/bash
openedWindows=$(/usr/bin/osascript ~/emacsWindowsCount.scpt)
if [ $openedWindows -eq 0 ]; then
    /Applications/Emacs.app/Contents/MacOS/bin/emacsclient -n -c -e  "(select-frame-set-input-focus (selected-frame))"
else
    open -a Emacs   
fi

code for "emacsWindowsCount.scpt" (used in the previous script, I have compiled the code with osacompile for performance)

tell application "System Events"
    if exists (process "Emacs") then
    else
        return 0
    end if
    tell application "Emacs"
        set numberOfWindows to (count windows)
    end tell
    return numberOfWindows
end tell    

I have mapped switchToEmacs.sh to a shortcut using Alfred 3 and it does what I expect it to do, but it is slow! Not extremely slow but the switch is not immediate and I have to wait about 0.3 seconds. Conversely if I have an emacs window opened and type "emacs" in the spotlight, then the transition is immediate, so I would like to remove that unnecessary waiting.

Since I hate that waiting time (it seems very short but when you need to navigate a lot trough applications it becomes awkward) for now I am doing the following: I have removed the emacs deamon, every time I log in I start emacs.app, when I need to close the emacs app I don't use CMD+Q but CMD+H, when I need to recall emacs I simply launch emacs.app (trough an Alfred 3 shortcut) so I get emacs focus. With this workaround the transition to emacs is immediate, but I would prefer my script for two reasons: first, with the script so I can use emacs from terminal before having launched an emacs instance opening emacs.app, but the real reason is that using this method if I type "emacsclient -t myFile" in terminal and then I close the buffer returning to the terminal, then the emacs windows (the emacs.app) will get the focus, even if I have not given it to it. This is really awkward.

IMPORTANT EDIT: I noticed that opening a new instance is immediate, what takes time is open -a Emacs. I have tried to replace it with tell application "Emacs" to activate window 1 (compiled) but it is still slow. Any ideas?

EDIT: I have achieved perfect performance using this free tool https://sabi.net/nriley/software/#appswitch Now there is still a little delay but it is due to the rest of the code.

Answer 1

I usually just run

emacsclient -a emacs FILE

or

emacsclient -a SHELL-SCRIPT-WHICH-STARTS-EMACS-WITH-PARAMETERS FILE

and let emacsclient figure out the rest.

Answer 2

Is it the osa script that's taking the time?

I use a similar approach to you, but do all the processing in bash. Here's the bash function I use (in Linux, I'm not near my Mac to verify portability at the moment):

ec ()
{
    running=$(pgrep -u $USER -c emacs)
    if [ $running -eq 0 ]; then
        emacs --geometry 85 --fullheight $* &
        return 0
    fi
    emacsclient --no-wait $*
    return 0
}