#+BEGIN_SRC ___ ___ ___ ___ ___ ___ ___ / /\ /__/\ / /\ /__/\ / /\ / /\ / /\ / /:/ \ \:\ / /:/_ | |::\ / /::\ / /:/ / /:/_ / /:/ \__\:\ / /:/ /\ | |:|:\ / /:/\:\ / /:/ / /:/ /\ / /:/ ___ ___ / /::\ / /:/ /:/_ __|__|:|\:\ / /:/~/::\ / /:/ ___ / /:/ /::\ /__/:/ / /\ /__/\ /:/\:\ /__/:/ /:/ /\ /__/::::| \:\ /__/:/ /:/\:\ /__/:/ / /\ /__/:/ /:/\:\ \ \:\ / /:/ \ \:\/:/__\/ \ \:\/:/ /:/ \ \:\~~\__\/ \ \:\/:/__\/ \ \:\ / /:/ \ \:\/:/~/:/ \ \:\ /:/ \ \::/ \ \::/ /:/ \ \:\ \ \::/ \ \:\ /:/ \ \2.0 /:/ \ \:\/:/ \ \:\ \ \:\/:/ \ \:\ \ \:\ \ \:\/:/ \__\/ /:/ \ \::/ \ \:\ \ \::/ \ \:\ \ \:\ \ \::/ /__/:/ \__\/ \__\/ \__\/ \__\/ \__\/ \__\/ \__\/ 222222222222222 2:::::::::::::::22 2::::::222222:::::2 2222222 2:::::2 2:::::2 2:::::2 2222::::2 22222::::::22 22::::::::222 2:::::22222 2:::::2 2:::::2 2:::::2 222222 2::::::2222222:::::2 2::::::::::::::::::2 22222222222222222222 #+END_SRC * Chemacs Chemacs 2 is an Emacs profile switcher, it makes it easy to run multiple Emacs configurations side by side. Think of it as a bootloader for Emacs. ** Differences from Chemacs 1 Emacs intialization used to have a single entry point, either =~/.emacs= or =~/.emacs.d/init.el=. More recent Emacsen have introduced a second startup script, =~/.emacs/early-init.el=, which runs earlier in the boot process, and can be used for things that should happen very early on, like tweaking the GC, or disabling UI elements. Chemacs 2 supports =early-init.el=, Chemacs 1 does not. This does also imply that Chemacs 2 needs to be installed as =~/.emacs.d= (a directory), rather than simply linking it to =~/.emacs= (a single file). ** Rationale Emacs configuration is either kept in a =~/.emacs= file or, more commonly, in a =~/.emacs.d= directory. These paths are hard-coded. If you want to try out someone else's configuration, or run different distributions like Prelude or Spacemacs, then you either need to swap out =~/.emacs.d=, or run Emacs with a different =$HOME= directory set. This last approach is quite common, but has some real drawbacks, since now packages will no longer know where your actual home directory is. All of these makes trying out different Emacs configurations and distributions needlessly cumbersome. Various approaches to solving this have been floated over the years. There's an Emacs patch around that adds an extra command line option, and various examples of how to add a command line option in userspace from Emacs Lisp. Chemacs tries to implement this idea in a user-friendly way, taking care of the various edge cases and use cases that come up. ** Installation Clone the Chemacs 2 repository as =$HOME/.emacs.d=. Note that if you already have an Emacs setup in =~/.emacs.d= you need to move it out of the way first. If you have an =~/.emacs= startup script then move that out of the way as well. #+BEGIN_SRC shell [ -f ~/.emacs ] && mv ~/.emacs ~/.emacs.bak [ -d ~/.emacs.d ] && mv ~/.emacs.d ~/.emacs.default git clone https://github.com/plexus/chemacs2.git ~/.emacs.d #+END_SRC Note that this is different from Chemacs 1. Before Chemacs installed itself as =~/.emacs= and you could have your own default setup in =~/.emacs.d=. This approach no longer works because of =~/.emacs.d/early-init.el=, so Chemacs 2 needs to be installed as =~/.emacs.d=. Next you will need to create a =~/.emacs-profiles.el= file, for details see below. #+begin_src emacs-lisp (("default" . ((user-emacs-directory . "~/.emacs.default")))) #+end_src ** Usage Chemacs adds an extra command line option to Emacs, =--with-profile=. Profiles are configured in =~/.emacs-profiles.el=. If no profile is given at the command line then the =default= profile is used. #+BEGIN_SRC shell $ emacs --with-profile my-profile #+END_SRC There is an option for using profile that is not preconfigured in =~/.emacs-profiles.el=. To accomplish that you can directly provide the profile via the command line, like so #+BEGIN_SRC shell $ emacs --with-profile '((user-emacs-directory . "/path/to/config"))' #+END_SRC This method supports all the profile options given below. ** .emacs-profiles.el This file contains an association list, with the keys/cars being the profile names, and the values/cdrs their configuration. The main thing to configure is the =user-emacs-directory= #+BEGIN_SRC emacs-lisp (("default" . ((user-emacs-directory . "~/.emacs.default"))) ("spacemacs" . ((user-emacs-directory . "~/spacemacs")))) #+END_SRC Chemacs will set this to be the =user-emacs-directory= in use, and load =init.el= from that directory. Other things you can configure - =custom-file= : The file where Customize stores its customizations. If this isn't configured, and the =custom-file= variable is still unset after loading the profile's =init.el=, then this will get set to the profile's =init.el= - =server-name= : Sets the =server-name= variable, so you can distinguish multiple instances with =emacsclient -s =. - =env= An association list of environment variables. These will get set before loading the profile, so they can influence the initialization, and they are visible to any subprocesses spawned from Emacs. - =straight-p= Enable the [[https://github.com/raxod502/straight.el][Straight]] functional package manager. Store =.emacs-profiles.el= together with your dotfiles. If you're not yet keeping a version controlled directory of dotfiles, then check out [[https://github.com/plexus/dotfiles/blob/master/connect-the-dots][connect-the-dots]] for a helpful script to do that. ** Changing the default profile (e.g. for GUI editors) Where it is not possible to use the =--with-profile= flag, the default profile can be set using a =~/.emacs-profile= file. If your =~/.emacs-profiles.el= file contains the following: #+BEGIN_SRC emacs-lisp (("default" . ((user-emacs-directory . "~/.emacs.default"))) ("spacemacs" . ((user-emacs-directory . "~/spacemacs"))) ("prelude" . ((user-emacs-directory . "~/prelude")))) #+END_SRC you can create a file called =~/.emacs-profile=, containing the name of the profile you'd like to be used when none is given on the command line: #+BEGIN_SRC shell $ echo 'spacemacs' > ~/.emacs-profile #+END_SRC This will set the default profile to be the "spacemacs" profile, instead of "default". You can change the default by simply changing the contents of this file: #+BEGIN_SRC shell $ echo 'prelude' > ~/.emacs-profile #+END_SRC If this file doesn't exist, then "default" will be used, as before. ** Spacemacs Spacemacs is typically installed by cloning the Spacemacs repo to =~/.emacs.d=, and doing extra customization from =~/.spacemacs= or =~/.spacemacs.d/init.el=. This makes it tedious to switch between version of Spacemacs, or between different Spacemacs configurations. With Chemacs you can point your =user-emacs-directory= to wherever you have Spacemacs installed, and use the =SPACEMACSDIR= environment variable to point at a directory with customizations that are applied on top of the base install. #+BEGIN_SRC emacs-lisp (("spacemacs" . ((user-emacs-directory . "~/spacemacs") (env . (("SPACEMACSDIR" . "~/.spacemacs.d"))))) ("spacemacs-develop" . ((user-emacs-directory . "~/spacemacs/develop") (env . (("SPACEMACSDIR" . "~/.spacemacs.d"))))) ("new-config" . ((user-emacs-directory . "~/spacemacs/develop") (env . (("SPACEMACSDIR" . "~/my-spacemacs-config")))))) #+END_SRC ** DOOM emacs You can add an entry similar to the following to your =.emacs-profiles.el= In the following snippet =~/doom-emacs= is where you have cloned doom emacs. (Depending on when you read this) =DOOMDIR= support is only in =develop= branch of doom emacs. Check commit history of =master= branch of doom emacs #+BEGIN_SRC emacs-lisp ("doom" . ((user-emacs-directory . "~/doom-emacs") (env . (("DOOMDIR" . "~/doom-config"))))) #+END_SRC Please refer to [[https://github.com/plexus/chemacs/issues/5][this]] discussion for details. ** FreeDesktop Directories Both =~/.emacs-profiles.el= and =~/.emacs-profile= can also be stored under =$XDG_CONFIG_HOME/chemacs= (typically =~/.config/chemacs=) as =$XGD_CONFIG_HOME/chemacs/profiles.el= and =$XDG_CONFIG_HOME/chemacs/profile= respectively. Further, as indicated by the [[http://git.savannah.gnu.org/cgit/emacs.git/tree/etc/NEWS?h=emacs-27][Emacs 27.1 changelog]], Emacs is now compatible with XDG Standards, looking for its configuration files in =${XDG_CONFIG_HOME}/emacs= directory too (provided the traditional =~/.emacs.d= and =~/.emacs= does not exist). Therefore, it is perfectly viable to install Chemacs 2 in =${XDG_CONFIG_HOME}/emacs= (usually =~/.config/emacs=) directory - with the aforementioned caveat: _the directory =~/.emacs.d"= and the file ="~/.emacs"= does not exist_. ** LICENSE Copyright © Arne Brasseur 2018-2020 Distributed under the terms of the GPL v3.