curspace

This is a simple command line tool that outputs a number identifying the current Space for Mac OS X.

The code is stolen from http://xmonad.org/

I extracted the appropriate bits and turned it into a simple XCode project.

I use it to have separate emacs instances on different Mac OS spaces such that invoking emacs filename in a terminal on that space opens the file in the emacs instance in that space.

This is the script I use to invoke emacs:

#!/bin/sh

EMACS=/usr/bin/emacs
EMACSCLIENT=/usr/bin/emacsclient

# if we have -nw on the command line, invoke a separate emacs instance
for ARG in $*; do
    if [ $ARG = "-nw" ]; then
        exec $EMACS $*
    fi
done

# otherwise send the file(s) to the emacs instance on this virtual desktop
if [ $OS = "Darwin" ]; then
    CURDESK=`curspace`
    EMACS=/Applications/Emacs.app/Contents/MacOS/Emacs
    EMACSCLIENT=/Applications/Emacs.app/Contents/MacOS/bin/emacsclient
else
    CURDESK=`wmctrl -d | grep '\*' | awk '{ print $1 }'`
fi

$EMACSCLIENT -s "server$CURDESK" --no-wait $* > /dev/null 2>&1
if [ $? != 0 ]; then
    # no instance running on this virtual desktop, so start one
    $EMACS $* &
    exit 0
fi

And my .emacs file contains:

;; if we're running on X Windows or the Mac, start up the server with a
;; server-name specialized to the virtual desktop we currently occupy; our
;; emacs launcher script will attempt to open new files using said server
(cond ((string= "x" window-system)
       (let ((cmd "wmctrl -d | grep '\*' | awk '{ print $1 }'"))
         (setq server-name (format "server%s" (chomp (shell-command-to-string cmd)))))
       (server-start))
      ((string= "ns" window-system)
       (setq server-name (format "server%s" (chomp (shell-command-to-string "curspace"))))
       (server-start))
      )

Happy hacking!