replace-regexp and numbering lines

I saw the Got Emacs? posting showing off the new emacs-24 rectangle-number-lines command, to number a bunch of lines in buffer, i.e..:

foo
bar
cuux

becomes:

1 foo
2 bar
3 cuux

Very cool! An alternative is to use cua-mode, mark the column for the numbers with cua-set-rectangle-mark (C-RET), and then use M-x cua-sequence-rectangle (which takes you throught the steps, and has a lot of flexibility.

But let's look at yet another way: using replace-regexp. If we select (mark) the list once more, we can do M-x replace-regexp RET ^ RET \#. RET Note that the # is a special meta-character that represents the number of replacements already made. This has the somewhat clumsy side-effect that your list be numbered, starting at 0 rather than 1, so you should add a dummy-element at the beginning. Clearly, replace-regexp is inferior for simply adding some line numbers – however, it has the flexibility to do some smarter things.

Smarter things? Yes! replace-regexp allows you to use arbitrary Lisp-expressions in the replace strings. So, let's suppose that we want to use letters instead of numbers for our lines. Easy – again, select (mark) your lines, M-x replace-regexp RET ^ RET \,(format "%c. " (+ ?a \#)) RET and we get:

a. foo
b. bar
c. cuux

Admittedly, not the most world-shattering thing, but it does show the powers hidden in something as common as replace-regexp.

who holds this value?

Something from the category of useful things hiding in emacs… Suppose you are looking for the variable that holds a certain value. How to find it?

Easy: M-x apropos-value

So, for example, finding all variables that hold your e-mail address:

M-x apropos-value RET me@example.com RET

and you'll get all the matches in the *Apropos*-buffer. HT: Stephen Eglen.

Also check the various other M-x apropos-... commands, they all help you find useful information if you can remember a word. Except for… M-x apropos-zippy… eh?

euro 2012 games in your org-mode agenda

Things have been rather quiet at emacs-fu - reason for this is that most of my emacs hacking time has been spent on mu4e, the emacs e-mail client I wrote. It's been shaping up pretty nicely, I should probably write some emacs-fu posts about it :)

Another interesting pastime (esp. in Europe) is football/soccer, in particular the Euro2012 games; long-time readers will remember the schedule for world cup games; I made a new one for Euro2012: https://github.com/djcb/org-euro2012.

In order to have the games show up in your agenda, make sure the file is in your org-agenda-files. If needed, you could add it with something like this in your org-mode settings (change the directory path to wherever you have put euro2012.org):

(add-to-list 'org-agenda-files "~/org/euro2012.org")

One small issue with the schedule is that it uses the central-european summer time (UTC+2), and there is no automatic way to adjust times for the local time zone. As a work-around, Juan Pechiar provided the following function which makes it easy to update all org-timestamps in a file:

(defun update-org-hours (n)
  "Change all org-mode timestamps in the current buffer by N hours."
  (interactive "nAdd hours: ")
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward "[[<]" nil t)
      (when (org-at-timestamp-p t)
        (org-timestamp-change n 'hour)))))

Evaluate this function. After that, you can go to the file with the schedule, and give an M-x update-org-hours, provide the offset for your timezone, compared to UTC+2.

Let the games begin!

social networking with bitlbee and erc

Instant messaging (IM) is one of the great time sinks of our age. Emacs-users, social butterflies as we are, of course want to take part in that -- preferrably from the comfort of our own environment.

There are various ways to use services like MS Live Messenger, Facebook Chat, GTalk, Yahoo etc. from within emacs – the one I use is called BitlBee. BitlBee is a program that presents all the various forms of IM as IRC-channels. In other words, while BitlBee knows all the details about communicating with these networks, all you need is an IRC-client to connect to BitlBee. This IRC-client does not have to be Emacs-based - any client can be used - but I am using ERC. Note, the below assumes you are somewhat familiar with it.

So, let's see how we can set up BitlBee on our system; there are public BitlBee-servers available online, but in the case of IM, I wouldn't necessarily want to trust them with my account data… so I'm using my own.

Setting up Bitlbee

So, how can we set this up? First, install BitlBee – many distributions have ready-made packages, otherwise you can build from source. In the examples below, I am assuming you are using Bitlbee version 3 or higher; if you use a different version, the details will vary a bit.

You can either run Bitlbee as a system-wide daemon, or just use it on your own. I am doing the former (for the latter, bitlbee.el is useful).

To connect ERC to the Bitlbee daemon, you can use something like the following:

(defun i-wanna-be-social ()
  "Connect to IM networks using bitlbee."
  (interactive)
  (erc :server "localhost" :port 6667 :nick "user"))

I'm sure you can come up with a better nick than user… Anyhow, with this function in your ~/.emacs, we can connect to bitlbee with:

M-x i-wanna-be-social RET

This should connect us to BitlBee; when all goes well, this will look something like this:

*** You have joined channel &bitlbee
*** mindcrime has changed mode for &bitlbee to +t
*** Users on &bitlbee: @user @root
*** Topic for &bitlbee: Welcome to the control channel. Type help for help
    information.
<root> Welcome to the BitlBee gateway!
<root>
<root> If you've never used BitlBee before, please do read the help
  information using the help command. Lots of FAQs are answered there.
<root> If you already have an account on this server, just use the identify
  command to identify yourself.
<root> The nick is (probably) not registered
*** &bitlbee modes: +t
<ERC>

Now, this first time, you will need to register yourself (this is only needed once); use the same nick (user in the example) that you used before:

<user> register user secretpassword
<root> Account successfully created

We're registered! This means, that bitlbee knows about you, and will save your settings.

Re-entering bitlbee

Just to complete the bitlbee-connecting part: the next time you want to use bitlbee, use i-wanna-be-social as before. However, now you need to identify yourself (rather than register):

<user> identify user secretpassword
<root> Password accepted, settings and accounts loaded

This can be automated by adding something like the following to your config:

(defun bitlbee-identify ()
  (when (and (string= "localhost" erc-session-server)
          (string= "&bitlbee" (buffer-name)))
    (erc-message "PRIVMSG" (format "%s identify user secretpassword"
                             (erc-default-target)
                             djcb-bitlbee-password))))

(add-hook 'erc-join-hook 'bitlbee-identify)

Modify user and secretpassword as desired. If you don't want write out your passwords in your emacs config files, take a look at keeping your secrets secret.

Adding accounts

Now, let's add some IM-accounts (just some examples here; also see Bitlbee Quickstart. Note, add any point during this, you can see your accounts with the command:

<user> account list

and using the numbers (or the accounts 'tag') you can switch an account on (and off):

<user> account 0 on

There are many other commands – use help command the consult the built-in documentation.

Connecting to IM networks

To connect to IM networks, you have to add the accounts to BitlBee. It will save them, so you only need to do that once. Let's do it - in each case, replace user and password with whatever you use for those.

You can see your combined logged-in buddy list using M-x erc-channel-names (or C-c C-n). Or use the blist command (see help blist).

After adding an account, it's a good idea to issue the save command, to ensure that bitlbee saves it.

Jabber

<user> account add jabber foobar@jabber.org mypassword
<root> Account successfully added with tag jabber
<user> account jabber on
<root> jabber - Logging in: Connecting
<root> jabber - Logging in: Connected to server, logging in
<root> jabber - Logging in: Converting stream to TLS
<root> jabber - Logging in: Connected to server, logging in
<root> jabber - Logging in: Authentication finished
<root> jabber - Logging in: Authenticated, requesting buddy list
<root> jabber - Logging in: Logged in

(and of course, you can use other servers beside jabber.org)

GoogleTalk

GoogleTalk (gtalk) is implemented using XMPP (jabber), and it's recommended to use oauth for authentication. Note, the foobar below is just a placeholder (for a password); bitlbee wants us to put something there, but since we'll be using oauth, it's not actually used.

<user> account add jabber myaccount@gmail.com foobar
<root> Account successfully added with tag gtalk
<user> account gtalk set oauth on
<root> oauth = `on'
<user> account gtalk set nick_source full_name
<root> nick_source = `full_name'
<user> account gtalk on
<root> gtalk - Logging in: Starting OAuth authentication

Now, a second window will open with a URL:

<jabber_oauth> Open this URL in your browser to authenticate:
https://accounts.google.com/o/oauth2/auth?scope=https://www.googleapis.\
com/auth/googletalk&response_type=code&redirect_uri=urn:ietf:wg:oauth:2.0:oob&client_i\
d=78312399893489.apps.googleusercontent.com

<jabber_oauth> Respond to this message with the returned authorization
token.

Follow this URL in your browser, and it will take you to some Google page for authentication. When that is completed, you will receive some string cookie, which you paste back into the newly opened window.

<user> 4/sIns904fdlkP5nudjCF4mBHF7Go_-E0g8
*** jabber_oauth is AWAY: Offline

Et voilà! We're connected to Gtalk (don't worry about the Offline-warning).

Facebook

Apart from being a social website, Facebook can also be used for IM. You can do this through the website, or you can use its jabber interface. It works very similar to gtalk; only important thing is that you get yourself a Facebook username:

<user> account add jabber myusername0@chat.facebook.com
<root> Account successfully added with tag fb
<root> You can now use the /OPER command to enter the password
<root> Alternatively, enable OAuth if the account supports it: account
  fb set oauth on
<user> account fb set oauth on
<root> oauth = `on'
<user> account gtalk set nick_source full_name
<root> nick_source = `full_name'
<user> account fb on
<root> fb - Logging in: Starting OAuth authentication

Then, go through the oath-authentication steps (see the discussion about adding Gtalk accounts above).

Once authenticated, you'll get something like this:

<root> fb - Logging in: Requesting OAuth access token
<root> fb - Logging in: Connecting
<root> fb - Logging in: Connected to server, logging in
<root> fb - Logging in: Converting stream to TLS
<root> fb - Logging in: Connected to server, logging in
<root> fb - Logging in: Authentication finished
<root> fb - Logging in: Server claims your JID is
  `-748234518@chat.facebook.com' instead of
  `myusername0@chat.facebook.com'. This mismatch may cause problems with
  groupchats and possibly other things.
<root> fb - Logging in: Authenticated, requesting buddy list
<root> fb - Logging in: Logged in

It's to now act upon the warning, so, we log out, change the user name and long back in:

<user> account fb off
<root> fb - Signing off..
<user> account fb set username -748234518@chat.facebook.com
<root> username = `-748234518@chat.facebook.com'
<user> account fb on

MSN / Live Messenger

MSN uses its own protocol (although apparently they're also supporting XMPP ("jabber") now). Suppose you have an account there, user partygirl89@hotmail.com with password iamcute:

<user> account add msn partygirl89@hotmail.com iamcute
<root> Account successfully added
<user> account msn on
<root> msn - Logging in: Connecting
<root> msn - Logging in: Connected to server, waiting for reply
<root> msn - Logging in: Transferring to other server
<root> msn - Logging in: Connected to server, waiting for reply
<root> msn - Logging in: Authenticated, getting buddy list
<root> msn - Login error: Error reported by MSN server: Invalid
       (non-existent) handle                                      [12:17]
<root> msn - Logging in: Logged in

The 'Error reported' does not seem to matter.

Other accounts

It's similarly easy to setup Twitter-accounts and Identi.ca-accounts; I've stopped using those though, as it turned out to be a little too easy for some typing in the wrong window to end op as a tweet… The risk is less with twittering-mode and identica-mode.

For ICQ/Yahoo/AIM see below – replace the username/password with your own.

• ICQ
  

  <user> account add oscar ICQ-ID PASSWORD login.icq.com
  <root> ...
  

• AIM
  

  <user> account add oscar AIM-NICK PASSWORD login.aol.oscar.com
  <root> ...
  

• Yahoo!
  

  <user> account add yahoo YAHOO-NICK PASSWORD
  <root> ...
  

  And I'm not even talking about combining bitlbee and Skype – yes, that is possible, too.

Chatting

Now, chatting is easy, following the normal ERC conventions (and settings). When people talk to you, a window opens (or a frame – see erc-auto-query. And you can initiate conversations with people by using /msg nick, with nick of course being the nickname of the person you want to talk to.

ERC/Bitlbee also work together nicely with Sauron, the emacs event tracker.

Have fun! I have only scratched the surface here - you now have the full arsenal of Elisp and ERC power available for your chatting.

special characters

Special characters

Living in a post-ASCII world offers great opportunities, but brings some problems, too. After all, it's nice to be able to write Ångström or Καλημέρα or ☺☎☯, but it's not necessarily easy to enter those characters.

input methods

So - what to do? First, you can set the input-method, as explained in the emacs manual. This is the best solution if you're writing a non-Latin language – Russian, Thai, Japanese, …

If you only occasionally need some accented character, input methods like latin-postfix (e" -> ë), latin-prefix ("e -> ë) or TeX (\"e -> ë) are useful. They also tend to annoy me a bit, as they often assume I need an accented character, when all I want is to put a word in quotation marks…

compose key

Another method is to use a special compose key; for example, under Gnome 3 it's in the the Region and Language applet, under Options..., in Gnome 2 it's in the Keyboard applet in Layouts/Options…. This works for all programs, not just emacs (see this Ubuntu help page for some details). I've set my Compose-key to Right-Alt, so Right-Alt "e -> ë.

Using the compose key works pretty well for me; setting the input method may be more convenient when you need to write a lot of accented characters.

Now, his may be good and well for the accented characters and other variants of Latin characters, such as the German Ess-Zet ligature "ß" (note, you can get that character with latin-prefix "s -> ß, latin-postfix s" -> ß or <compose-key> ss -> ß). But what about Greek characters? Mathematical symbols? Smileys?

ucs-insert

One way to add characters like α, ∞ or ☺ is to use ucs-insert, by default bound to C-x 8 RET. If you know the official Unicode name for a character, you can find it there; note that there's auto-completion and you can use * wild-cards. For the mentioned characters, that would be GREEK SMALL LETTER ALPHA, INFINITY and WHITE SMILING FACE.

You can also use the Unicode code points; so C-x 8 RET 03b1 RET will insert α as well, since its code point is U+03B1. In case you don't know the code points of Unicode characters, a tool like the Character Map (gucharmap) in Gnome may be useful.

abbrev

Since ucs-insert may not be convenient in all cases, you may want to add shortcuts for oft-used special characters to you abbrev table. See the entry on Abbrevs in the emacs manual. I usually edit the entries by hand with M-x edit-abbrevs, and I have entries like:

(text-mode-abbrev-table)
"Delta0"       0    "Δ"
"^2"           0    "²"
"^3"           0    "³"
"almost0"      0    "≈"
"alpha0"       0    "α"
"any0"         0    "∀"
"beta0"        0    "β"
"c0"           0    "©"
"deg0"         0    "℃"
"delta0"       0    "δ"
"elm0"         0    "∈"
"epsilon0"     0    "ε"
"eta0"         0    "η"
"heart0"       0    "♥"
"inf0"         0    "∞"
"int0"         0    "∫"
"notis0"       0    "≠"

Now, alpha0 will be auto-replaced with α. I'm using the 0 suffix for most entries so I can easily remember them, without making it hard to use alpha as a normal word. Note, abbrevs are a bit picky when it comes to the characters in the shortcut – for example, setting != -> ≠ won't work.

inheriting abbrevs from other modes

If you have set up a nice set of abbreviations for text-mode, you may want to use them in other modes as well; you can accomplish this by including the text-mode abbreviations into the table for the current one, for example in your ERC setup:

;; inherit abbrevs from text-mode
(abbrev-table-put erc-mode-abbrev-table :parents (list text-mode-abbrev-table))

update

Regular emacs-fu programming will resume shortly, but for now I'll provide a brief update on some of my projects.

• Recently, I discussed sauron, and event-tracking tool for emacs. I added some new features, fixed some bugs, and got some contributions (yay!)
  • tweak/improve priority handling
  • add a backend for the emacs-24 notification system
  • add settings to make the sauron frame 'sticky', and to hide the mode-line
  • enable dbus-message source outside your session; useful for cron/procmail etc.
  • display events in a tabular fashion
  • add support for John Wiegley's event.el
  • much improved documentation
  • other things…

  Sauron version 0.2 is available through Marmalade (see Package Management Revisited)

• I released version 0.9.8 of mu (e-mail searcher/indexer, previously discussed in Searching e-mails with Wanderlust and mu). Now, for emacs-users I've added mu4e (manual), a new & experimental e-mail client. It won't be big and professional like gnus, but it's fun to hack on, and I've been using it for a few months.

sauron: keeping an eye on what's going on

I'm a fairly busy person, and need to keep track of a lot of things. That includes following a bunch of internal IRC channels, attending meetings, meeting deadlines and so on. But I don't want to stare at my org-mode calendar, or flip through ERC buffers all the time.

Instead, I'd like to have one little emacs frame (window) that gathers these ('events'), and transfers me to wherever the event came from when I click it - some IRC-channel in ERC, my org-calendar etc. and other inputs. Note, using Bitlbee, you can include Facebook-contacts, GoogleTalk-buddies and Twitter-tweets, … in ERC - so, you can track just about anything.

In addition, with so many inputs, I'd also like the possibility to filter out unwanted events, and generate various light/sound effects and fireworks, proportional to the priority of the event.

For all this, I wrote a little emacs-tool called Sauron that does just that. M-x sauron-start pops up a frame that receives events, and M-x sauron-stop hides it and stops listening. It works with ERC, org, and listens for D-Bus messages; so it's pretty easy to get events from all over the place.

It's a bit of a balancing act to get all the important information while not being swamped in noise, but Sauron allows you to fine-tune it to whatever works the best for you. I've tried to have sane defaults though, so things should mostly work without too much configuration - but if you need the power, it's there. I also added some convenience functions to make it easy to get sounds and other special effects.

So - it's brand new, it is of seems-to-work-for-me-quality, and I'd like to invite others to try it out, hack it, give feedback, add new back-ends and so on – what better Christmas present to ask for!

There's documentation, examples etc. to be found in Sauron's github repository.