How to connect to a running SWANK instance in SBCL with SLIME
WARNING! I am NOT an expert Common Lisp developer, I just try to learn and practice it! WARNING!
While I develop in Common Lisp I usually work on different projects in parallel.
Sometimes I stop working on them for a short time, or I restart my EMACS for some reason.
This is why I run multiple SBCL instances, start up SWANK in them, and I just connect my SLIME to the instance I want to work on.
Prerequisites
Obviously I installed & configured my EMACS, SLIME, quicklisp and SBCL.
I do not write more about their configuration in this post.
To be able to use history in SBCL I installed rlwrap, the readline wrapper, and use SBCL with it.
Installing it on Ubuntu is easy with APT.
sudo apt install rlwrap
Starting the SBCL then with rlwrap:
rlwrap sbcl
I see the Common Lisp REPL from this point.
Start SWANK in SBCL
The following commands are issued in the SBCL REPL!
Load SWANK and start the server in the running SBCL instance
(ql:quickload :swank) (swank:create-server :dont-close t)
Now the SWANK server is started and it is possible to connect to it with SLIME.
It binds to the port 4005 by default. To change the default port I change the create server line to something like
(swank:create-server :port 4008 :dont-close t)
The above command ensures with the :dont-close t option that the server will not stop when we disconnect from it.
Connecting to the server with SLIME
The following commands are issued in the EMACS!
Connecting the the server that is running on the same machine is quite easy.
M-x slime-connect RET
This will connect my SLIME to the port 4005 of my SWANK server on localhost by default.
When I need more instances I just change the port with the :port 4006 option.
Disconnecting is easy as well.
M-x slime-disconnect RET
Common Lisp is fun to learn, and opens a new perspective to the world of thinking!