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Didier Verna's scientific blog: Lisp, Emacs, LaTeX and random stuff.

Tuesday, September 3 2013

Menu bar icons for Emacs

Note: the feature described below is now available in the cutebar branch of my Emacs fork on GitHub.

A huge peeve of mine on OS X is the mixture of the (application) menu bar, starting on the left, and the status bar, starting on the right: when you have a lot of status indicators like me, even a reasonably sized application menu bar will irreparably hide a lot of status, which is really annoying.

One day, I had this idea that application menu bar (wide) titles could be replaced with (narrow) icons, hence leaving more space to the status bar. Of course, it shouldn't be up to the menu, or even to the application itself to choose which icon to use. It should be up to the user. A user will want a single icon set to work with all applications (e.g. you choose a nice File icon, and you want all applications to use it instead of the word "File").

So one day, I implemented a SIMBL plugin and preference pane for doing exactly that. Don't look for it, it's never been released. It lets the user create associations between menu titles and icons and hijacks OS X applications to modify the appearance of their menu bar. Alas, it doesn't work very well. Native Cocoa applications not doing anything fancy with their menus are ok, but most other applications are not.

Emacs menu bar icons Today, let me introduce some support for this feature in Emacs. Attached to this article is a patch against the current trunk plus a small image file. For this to work, you will need to put the image file (barsplit.png) in the etc/images/ directory of Emacs'source tree, apply the patch and recompile (--with-ns of course). Then, find yourself a nice set of icons and go customize the options menu-bar-use-icons, menu-bar-icons-directory and menu-bar-icons in the "menu" custom group. The docstrings should be self-explanatory. As you can see on the screenshot, what you get is a much narrower, visual menu bar. The first menu (the so-called "application menu") always uses the official application's icon. The other ones are your choice. Finally, the menu bar ends with a visual separator allowing to better distinguish its end from the start of the status bar.

The current implementation is very naive (sorry, I meant highly dynamic): titles / icons associations are recomputed every time the menu bar is redrawn. But this has in fact some advantages:

  1. the code is quite simple,
  2. customizations made by the user are visible immediately, without the need for a complex event listener / notification / whatever machinery (this machinery may already exist in the Emacs codebase though).

In fact, I've been using this patch for quite a while now and I didn't notice any performance impact on my 3 years-old Mac Book Pro. One last thing you need to know: the behavior of this feature may be unreliable (even if implemented correctly, which I think I did) because messing with the menu bar like this is uncharted territory, totally unsupported by Apple. Enjoy anyway :-)

Now, if somebody comes up with a nice and comprehensive set of menu bar icons for Emacs (and other OS X apps), I'd be delighted...

Tuesday, May 28 2013

el-rcfiles is released (first public version)

I've been using this for years, but never bothered to make it public until now.

el-rcfiles is a very small and simple library which provides Unix-like RC files for Emacs Lisp libraries. It's compatible with GNU Emacs and XEmacs, available in ELPA form, as a tarball and from GitHub. More details (including download) available here, but here is also the library's commentary section, for quick reference.

;;; Commentary:

;; The purpose of el-rcfiles is to provide the equivalent of traditional
;; Unix rc files (i.e. configuration files) for Emacs Lisp
;; libraries. The advantages of using configuration files are the
;; following:
;;   - your initialization file is less bloated,
;;   - since configuration files are lazily loaded, your Emacs session
;;     is (or begins) lighter. That is unless you already use lots of
;;     EVAL-AFTER-LOAD forms...

;; Usage:

;; 1. Load the library, go to the rcfiles Custom group and tweak (or not).
;; 2. Put a call to (rcfiles-register-rc-files) in your initialization
;;    file. This function can also be called interactively anytime you
;;    add, remove or modify a configuration file.
;; 3. Put your configuration code for a library `foo' in a file called
;;    `<rcfiles-directory>/foo<rcfiles-pseudo-extension>.el'.

Tuesday, May 14 2013

Emacs session bootstrap tweaks

This article essentially describes the top of my Emacs init file. That part of the code is devoted to modify the session bootstrap process, that is, some things that are normally done very early. It mostly deals with the package infrastructure but also contains a couple of other tricks that some people may consider useful. It goes like this…

The first line is self-explanatory (and please, be warned that I will discard any comment about it. You know why).

(require 'cl)

Platform-specific tweaks

A self-contained Emacs.app on MacOS X has its own site-lisp directory, but I want to make sure that the standard Unix one is here as well, and takes precedence.

(when (featurep 'ns)
  (add-to-list 'load-path "/usr/local/share/emacs/site-lisp"))

Updated When /not/ starting Emacs from the command-line (e.g. MacOS X app clicks or Quicksilver/Alfred, Unitiy launcher on Ubuntu etc.), I don't necessarily get my environment-based exec-path which can be problematic (e.g. for finding auxiliary programs such as movemail, gpg etc.). Emacs used to store the build-time value of exec-path in the custom's standard-value property, which was convenient for me because since I compile it myself, I could reuse that. This has changed however since this commit:

commit 2fc11b3fa3418e0e8a624376ea8bf4cbc70c2657
Author: Ludovic Courtès <ludo@gnu.org>
Date:   Mon Apr 20 17:44:23 2015 -0400

So now instead, I have patched it to save the build-time value in a new variable called BUILD-TIME-EXEC-PATH.

(when (boundp 'build-time-exec-path)
  (mapc (lambda (path) (setq exec-path (remove path exec-path)))
  (setq exec-path (append build-time-exec-path exec-path)))

ELPA infrastructure

Initialize ELPA now so that the rest of the initialization process may rely on packages without having to go through after-init-hook.

(require 'package)

I want system-wide directories to be named emacs-packages instead of site-lisp/elpa.

(setq package-directory-list
      (let (result)
        (dolist (path load-path)
          (and (stringp path)
                 (equal (file-name-nondirectory path) "site-lisp")
                 (push (expand-file-name "emacs-packages"
                                                       (directory-file-name path)))
	(nreverse result)))

I want my local directory to follow the same convention.

(setq package-user-dir "~/.emacs.d/emacs-packages")

Now, it's okay to initialize ELPA.


Now that the packages have been initialized, I actually want ELPA to install in /usr/local/share/emacs/emacs-packages by default, and keep my local directory for manual installations. One simple way to achieve that is to set my local directory to /usr/local/share/emacs/emacs-packages and to remove that from the system-wide directory list. One small drawback of this is that my local path is gone, so any new package installed there won't be seen until the next restart. This is not much of a problem though.

(setq package-user-dir "/usr/local/share/emacs/emacs-packages"
        package-directory-list (remove "/usr/local/share/emacs/emacs-packages"

Site and local (non ELPA) packages infrastructure

The purpose of this other infrastructure is to support packages that would be installed manually, outside ELPA, and in a way similar to XEmacs packages. A packages directory has lisp/, etc/ and info/ subdirectories. Every package installs its stuff directly in etc/ and info/, but adds its own subdirectory to lisp/ and puts its code (including a potential autoloads file) in there.

This additional infrastructure comes in handy in several situations. For instance, having Slime (auto)loaded in your session now becomes as simple as this:

ln -s /path/to/slime /usr/local/share/emacs/local-packages/lisp/

(defun dvl-initialize-packages (directory)
  "Initialize non-ELPA packages DIRECTORY.
This means:
  - adding the whole lisp/ subtree to LOAD-PATH,
  - loading the autoload files found there.
  (let ((default-directory (expand-file-name "lisp" directory)))
    ;; 1. Update LOAD-PATH
    (setq load-path
	   (let ((load-path (copy-sequence load-path)))
	     (append (copy-sequence (normal-top-level-add-to-load-path '(".")))
    ;; 2. Load autoload files
    (loop for directory in load-path
	    while (string-prefix-p default-directory directory)
	    do (mapc #'load (directory-files directory t "-autoloads\\.el$"))))
  ;; 3. Update the default Info directory list
  (add-to-list 'Info-default-directory-list
   (expand-file-name "info" directory)))

(require 'info)

Be sure to do this by increasing priority order.

(mapc #'dvl-initialize-packages

And now we can re-initialize Info with the proper defaults.

(setq Info-directory-list nil)

Custom settings

Now that we have bootstrapped the complete packages infrastructure, we can set the Custom file to something that makes sense and load it now.

(setq custom-file "~/.emacs.d/custom.el")
(load custom-file)

RC Files

Finally, install the rc files loader and we're done bootstrapping.


That completes my session bootstrap process.

Tuesday, January 17 2012

Patcher 4.0 is released

I'm happy to announce the release of Patcher version 4.0. This is a major release introducing many new features and enhancements.

Patcher is a tool designed to automate and ease the maintenance of archive-based projects. It provides assistance in building, reporting and committing patches, as well as in handling the corresponding ChangeLog entries, for example by creating skeletons. Patcher is the official tool for XEmacs development.


  • Support floating projects and temporary relocation allowing to use the same project descriptor for various directories.
  • Support for automatic detection of submodules via the :submodule-detection-function project option and the patcher-detect-submodules function. Currently supported RCS submodules are Mercurial and Git via the functions 'patcher-hg-detect-submodules.
  • Support ephemeral ChangeLogs thanks to a new :change-logs-status project option. Ephemeral ChangeLogs are not stored in ChangeLog files, but exist only temporarily for mail or log message insertion (See ChangeLogs Status in the documentation).
  • ChangeLog minor mode providing easy navigation through the mail/ChangeLog buffers cycle via C-c C-p n, C-c C-p p, C-c C-p N, C-c C-p P and C-c C-p m (See ChangeLogs Navigation in the documentation).
  • Support for switching to mail buffer and inserting ChangeLogs at once via C-c C-p l from ChangeLog buffers.
  • patcher-mail-insert-change-logs gets a prefix argument allowing to temporarily change the ChangeLogs appearance. It also supports inserting ChangeLogs even when the project is set not to.
  • Additional binding for patcher-logmsg-commit: C-c C-p c
  • Commit command buffer is now editable Commit is done via C-c C-p c or C-c C-c (patcher-cmtcmd-commit).
  • Fontification of commit command and log message buffers with comment syntax and initial informative help. See new Patcher faces.
  • Support for commit or log message canceling via C-c C-z.
  • Support for project abortion via C-c C-p k or C-c C-k in all relevant buffers, including ChangeLogs.
  • Support Subject: header modification in mail adaptation routines via a new project option :subject-rewrite-format.
  • Support project-wide dynamic subject modification via C-c C-p S in both mail and log message buffers.
  • Implement :kill-source-files-after-sending project option
  • Support for source file saving
  • Support for CVS diff's broken exit code policy via a new project option: :ignore-diff-status.


  • Improved support for temporary subprojects making them behave like permanent ones (with a specific subdirectory and set of files).
  • Much better error handling including exit code checking for external processes.
  • Improved support for overlapping Patcher instances through buffer and file referencing for both ChangeLog and source files.
  • Documentation rewrite and sections organization cleanup
  • More checks for project consistency including missing or spurious ChangeLog entries, source diffs, undiffable and uncommittable projects etc.
  • Improved project rediffing including support for partially generated ChangeLog skeletons, and interactive prompting for skeleton un/re-generation.


  • Mercurial themes renamed from 'mercurial to 'hg in order to remain consistent with the other RCS theme names.
  • ChangeLogs insertion in mail buffers rebound to C-c C-p l
  • Compressed ChangeLogs insertion in logmsg buffers rebound to C-c C-p L
  • Removed directory-sep-char hacks until the need for it raises again. Probably better implemented via project options anyway.
  • Diff commands can no longer be changed from patcher-mail-adapt but instead, the prefix argument allows for temporary subproject specification.
  • patcher-*-subproject entry points removed since they are no longer needed (see above).
  • Removed :kill-source-file-after-diffing option
  • :kill-source-files-after-sending renamed to :kill-sources-after-sending
  • patcher-mail-check-change-logs-insertion is now a project option named :check-change-logs-insertion.
  • patcher-mail-check-commit-action is now a project option named :check-commit.
  • :change-logs-diff-command option now understands nil instead of 'diff
  • The 'packed ChangeLogs appearance has been renamed to 'pack

Tuesday, December 27 2011

XEmacs now has a "foreback" face property

The "foreback" face property at workHere's another new face property in XEmacs. This one is probably not going to be used ever, but still it fixes one particular problem. Until now, XEmacs used the background and foreground colors to display a face background bitmap (as opposed to a regular pixmap). This basically rendered the text unreadable.

The new face property is called "foreback" (I'm running short of sensible property names these days). It's the "foreground of the background" if you will. When a face has a background bitmap, it uses the regular background color for bitmap's background, but the foreback color for the bitmap's foreground. See the attached screenshot for a concrete example of the problem it fixes.

The bitmap I used for this example is X11's xsnow bitmap. Nice Christmas XEmacs screenshot, isn't it? :-)

In order to set a face's foreback color, either use the Custom interface, or the set-face-foreback function.

Thursday, December 22 2011

XEmacs now has a "flush" face property

The "flush" face property at workI have just implemented a new face property in XEmacs 21.5, called "flush". When some text is displayed in a face which has this property set to t (it's a Boolean property), then the face extends until the right border of the window instead of just the end of the actual line of text. The effect is only visible if the face has a non-default background color or pixmap and gives the text segment the appearance of a block instead of being ragged right. In fact (if that rings a bell to you), this is the equivalent of the block value for the HTML display property.

See the attached screenshot for an example. In that particular case, the buffer displays an article in Gnus and the concerned face is mm-uu-extract. You can see two versions of the same buffer, with and without the property set. There are a number of situations in which setting a face to flush is nicer visually. Probably the most obvious case is that of text selection. Below is a list of faces that I'm currently setting to flush. I'll be updating this list as needed. In order to set a face to flush, either use the Custom interface or the set-face-flush-p function directly.


Wednesday, April 27 2011

XEmacs 21.5.30 "garlic" is released

At long last, there is a new release of XEmacs 21.5. A lot of stuff has happened in this release, but the most important thing is that this is the last GPLv2 version of XEmacs. Future versions (including the current trunk) will be licensed GPLv3 or later. In fact, the first GPLv3 release, 21.5.31, is expected to follow this one by a couple of days. Thanks mostly to Aidan Kehoe, I'm also quite happy that XEmacs Lisp is more Common Lisp'y than ever.

Thursday, February 25 2010

Translucent XEmacs coming in hot !!

I'm uploading a set of changes to the XEmacs 21.5 Mercurial repository right now. These changes implement a new face property named "background-placement" which makes an XEmacs frame "slide" over a face's background pixmap when the property is set to 'absolute.

If you do this on the default face, then you can achieve some sort of pseudo-translucency, for example by using the same (or a darkened version of) the root window's background pixmap.

Here are a couple of screenshots that illustrate this.


Wednesday, February 27 2008

Patcher 3.10 is released

I'm happy to announce the release of Patcher 3.10. Patcher is an XEmacs package for automating the maintenance of version control system based projects. Patcher is the official tool for XEmacs development.

What's new in this version:

** New feature: provide built-in themes for some revision control systems
These are PRCS, CVS, Subversion, Darcs and Mercurial. Also coming with
whitespace-resistant counterparts.
** Documentation: a chapter on how to setup Patcher for XEmacs development
** Bugfixes:
*** Cleanup the log messages wrt trailing whitespaces
*** Correctly display a missing theme name in error message
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Copyright (C) 2008 -- 2013 Didier Verna didier@lrde.epita.fr