fetching elisp library from url

Question

I am using use-package in my .emacs and it is great. However occasionally I want to use a 3-rd party code which is not in [M]ELPA. Of course, I can download it but then I will need to maintain a copy of it on all the machines I use. Now I can just copy .emacs to a new machine, start emacs and it will download and install all packages. I wonder if there is anything similar for non-packaged libraries? Something which will fetch them via HTTP or git, compile and add to load path.

Here is an example of a package I want to use:

https://github.com/emacsmirror/emacswiki.org/blob/master/zoom-frm.el

I suspect that maybe el-get can do this but I am unsure. Maybe somebody can show me an example for this zoom-ftm.el?

Answer 1

I have not found any existing solution to do that and come up with my own:

;; Inspired by https://www.emacswiki.org/emacs/BookmarkPlus#BulkDownloadCompileLoad 
(defun fetch-and-load-elisp (pkg-name pkg-files base-url base-dir)
  (let ((pkg-dir (concat (file-name-as-directory base-dir) (symbol-name pkg-name))))
    (require 'url)
    (add-to-list 'load-path pkg-dir)
    (make-directory pkg-dir t)
    (mapcar (lambda (arg)
              (let ((local-file (concat (file-name-as-directory pkg-dir) arg)))
                (unless (file-exists-p local-file)
                  (url-copy-file (concat base-url arg) local-file t))))
            pkg-files)
    (byte-recompile-directory pkg-dir 0)
    (require pkg-name)))

(when (fetch-and-load-elisp 'zoom-frm '("frame-cmds.el" "frame-fns.el" "zoom-frm.el") "https://www.emacswiki.org/emacs/download/" "~/lisp/")
      (define-key ctl-x-map [(control ?+)] 'zoom-in/out)
      (define-key ctl-x-map [(control ?-)] 'zoom-in/out)
      (define-key ctl-x-map [(control ?=)] 'zoom-in/out)
      (define-key ctl-x-map [(control ?0)] 'zoom-in/out))

I am not proficient in ELISP, and perhaps it could be improved. Error handling comes to mind. Also, the byte compilation is now run every time, even when files were unchanged.