Re: user-controlled load-path extension: load-dir

[Ben Key <bkey76@gmail.com>]

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Hello,

I have attached to this message version 4 of user-load-dir.el.

Several changes have been made to this version.

   1. The error handling in load-dir actually works as expected.  If one of
   the files in the user-load-dir generates an error, it is silently ignored
   and load-dir continues to load all the other files in the user-load-dir.
   2. Added the function byte-compile-dir to user-load-dir.el.  This
   function can be used to byte compile all files in the directory specified by
   the directory parameter.  If the optional parameter recurs is non-nil, this
   is done recursively.
   3. Added the function byte-compile-user-load-dir-files.  This interactive
   function may be used to byte compile all files in the user-load-dir.
   4. The function load-user-load-dir-files does nothing if user-load-dir is
   nil.
   5. Modified the user-load-dir defcustom so that it is set to t instead of
   nil in the case that it cannot be initialized at load time due to
   user-init-file being nil.
   6. Modified user-load-dir-after-init-hook so that it only sets
   user-load-dir to its default value if it is equal to t.

The reason I made changes 5 and 6 is to allow for the possibility of this
feature being disabled by the user setting user-load-dir to nil.

Setting auto-load-files-in-user-load-dir to nil causes to not be called
automatically by the user-load-dir-after-init-hook but the files can still
be called by calling load-user-load-dir-files interactively.  Setting
user-load-dir
to nil disables load-user-load-dir-files and
byte-compile-user-load-dir-files.

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[-- Attachment #2: user-load-dir.el --]
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;;; user-load-dir.el -- A quick and dirty implementation of a user load
;;; directory.  This file is provided as a possible answer to the
;;; "user-controlled load-path extension: load-dir" discussion on the
;;; emacs-devel list found at
;;; <http://lists.gnu.org/archive/html/emacs-devel/2011-03/msg00048.html>.

;;; This could eventually be turned into an Emacs package that can be
;;; installed via package.el.  For now, this file can be installed by
;;; placing it somewhere in your load path and add the line
;;; (require 'user-load-dir)
;;; to your .emacs or site-start.el file.

;;; Copyright (c) 2011 Ben Key

;; This file is free software: you can redistribute it and/or modify it
;; under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; This file is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with the bk-emacs-tools package.  If not, see
;; <http://www.gnu.org/licenses/>.

(if (not (boundp 'directory-files-no-dot-files-regexp))
	(defconst directory-files-no-dot-files-regexp
	  "^\\([^.]\\|\\.\\([^.]\\|\\..\\)\\).*"
	  "Regexp matching any file name except \".\" and \"..\".")
  )

(defcustom user-load-dir
  (if (not (null user-init-file))
	  ;; If this file is loaded from site-start.el, `user-init-file'
	  ;; will be nil, this will cause `file-name-directory' to throw an
	  ;; error due to the argument not being a string.  As a result, we
	  ;; only attempt to set the default value of `user-load-dir' here
	  ;; if `user-init-file' is not nil.
	  (format "%s.emacs.d/load.d" (file-name-directory (expand-file-name user-init-file)))
	t
	)
  "A user defined directory in which the user can place .el files that
will automatically be loaded after Emacs initialization is complete."
  :type 'directory
  :group 'initialization
  :require 'user-load-dir
  )

(defcustom load-files-in-user-load-dir-recursively nil
  "Non-nil causes `load-user-load-dir-files' to load all .el or .elc
files in the `user-load-dir' and in all subdirectories of the
`user-load-dir.'  Nil causes `load-user-load-dir-files' to load only
the files in the `user-load-dir.'

The default value is nil."
  :type 'boolean
  :group 'initialization
  :require 'user-load-dir
  )

(defcustom auto-load-files-in-user-load-dir t
  "Non-nil causes `load-user-load-dir-files' to be called automatically
from the `after-init-hook.'  Nil suppresses this automatic loading.
Note that since `load-user-load-dir-files' is an interactive function,
you may call it manually by using 'M-x load-user-load-dir-files' if you
choose to set this variable to nil.

The default value is t."
  :type 'boolean
  :group 'initialization
  :require 'user-load-dir
  )

(defun load-dir (directory &optional recurse)
  "Load all Emacs Lisp files in DIRECTORY.
If RECURSE is non-nil, recursively load all such files in all
subdirectories.

This function is based on one written by Evans Winner.  See the message
<http://lists.gnu.org/archive/html/emacs-devel/2011-03/msg00239.html>
for details."
  (interactive "D")
  (let (this-file loaded-files-list)
	(dolist 
		(file 
		 (directory-files
		  (expand-file-name directory) 
		  t directory-files-no-dot-files-regexp) nil)
	  (cond
	   ((and recurse (file-directory-p file))
		(when recurse (load-dir file))
		)
	   ((string-match "\\.el$\\|\\.elc$" file)
		(setq this-file (file-name-sans-extension file))
		(if (not (member this-file loaded-files-list))
			(progn
			  (setq loaded-files-list (add-to-list 'loaded-files-list this-file))
			  (ignore-errors
				(load this-file))
			  )
		  )
		)
	   )
	  )
	)
  )

(defun load-user-load-dir-files ()
  "Loads all .el files found in the `user-load-dir.'"
  (interactive)
  (if (not (null user-load-dir))
	  (load-dir user-load-dir load-files-in-user-load-dir-recursively)
	)
  )

(defun byte-compile-dir (directory &optional recurse)
  "Byte compile all Emacs Lisp files in DIRECTORY.  If RECURSE is
non-nil, recursively byte compile all such files in all
subdirectories."
  (interactive "D")
  (dolist 
	  (file 
	   (directory-files
		(expand-file-name directory) 
		t directory-files-no-dot-files-regexp) nil)
	(cond
	 ((and recurse (file-directory-p file))
	  (when recurse (byte-compile-dir file))
	  )
	 ((string-match "\\.el$" file)
	  (ignore-errors
		(byte-compile-file file))
	  )
	 )
	)
  )

(defun byte-compile-user-load-dir-files ()
  "Byte compiles all .el files found in the `user-load-dir.'"
  (interactive)
  (if (not (null user-load-dir))
	  (byte-compile-dir user-load-dir load-files-in-user-load-dir-recursively)
	)
  )

(defun user-load-dir-after-init-hook ()
  "An `after-init-hook' function that is used to conditionally call
`load-user-load-dir-files' depending on the value of
`auto-load-files-in-user-load-dir'."
  (if (equal user-load-dir t)
	  ;; If this file is loaded from site-start.el, `user-load-dir' may
	  ;; be nil at this point.  See the comments for `user-load-dir'
	  ;; above. If this happens, use the default value here.
	  (setq user-load-dir
			(format "%s.emacs.d/load.d" (file-name-directory (expand-file-name user-init-file))))
	)
  (if auto-load-files-in-user-load-dir
	  (load-user-load-dir-files)
	)
  )

(add-hook 'after-init-hook 'user-load-dir-after-init-hook)

(provide 'user-load-dir)