Lacking Natural Simplicity

C.P. found Robert Smith's implementation of Bill Gosper's HASHLIFE algorithm and wanted my help with running it. I cloned the repo it was in and ran sbcl in the hashlife directory. Then I entered:

(asdf:operate 'asdf:load-op 'charmlife)

That resulted in a Component CHARMLIFE not found error in sbcl. I thought that was odd — it was right there in the current directory. I looked at asdf:*central-registry*, and the only thing in it was the quicklisp directory. The ASDF howto showed an example of setting asdf:*central-registry*:

(setf asdf:*central-registry*
  ;; Default directories, usually just the ``current directory''
  '(*default-pathname-defaults*

    ;; Additional places where ASDF can find
    ;; system definition files
    #p"/home/foo/lisp/systems/"
    #p"/usr/share/common-lisp/systems/"))

Noticing that it had the symbol *default-pathname-defaults* in the new value, I guessed that it being missing from mine caused ASDF to not find the system in the current directory. So I added it and tried again. This time ASDF couldn't find cl-charms. I guessed and used Quicklisp to load it. That worked. Then I looked at charmlife.lisp and looked at the main function and figured out how to run it and how to interact with the program when it was running.

Here's what I had to do:

(setf asdf:*central-registry*
      (cons '*default-pathname-defaults*
            asdf:*central-registry*))
(ql:quickload "cl-charms")
(asdf:operate 'asdf:load-op 'charmlife)
(charmlife:main)