Images in Emacs

Posted on 2012-09-27 by jcs

Christopher Wellons over at null program has a nifty post on rendering fractals in Emacs. He shows how to draw and display fractal using Emacs lisp. I didn’t know you could do stuff like that. The Elisp writes the image in Netpbm format and then switches the buffer to image-mode. The code is surprisingly simple.

None of this is going to change your life, probably, but it is a lot of fun and it shows off the amazing versatility of Emacs. Head on over and take a look just for fun. You might also want to experiment a bit to see what pretty pictures you can come up with.

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Security Roundup

Posted on 2012-09-26 by jcs

It’s been a busy week on the security front. Of course, that’s true of most weeks but here’s some interesting stories from the past few days:

  • CloudCracker is offering a special this week on their MS-CHAPv2 service. They will break any MS-CHAPv2 password for only $20, a $180 discount. As CloudCracker puts it

    This means that any PPTP VPN connection or intercepted MS-CHAPv2 WPA
    Enterprise wireless credentials can be cracked and decrypted with a
    100% success rate for only $20.

  • The IEEE (!) had a “data breach” in which 100k of plaintext passwords were exposed on their FTP site for over a month. I don’t know what else can be said about this.
  • Hotmail is helpfully (and silently) shortening users’ passwords to 16 characters. Honestly, there’s really no reason or excuse for this. If they were doing things correctly, they’d be hashing those passwords with bcrypt or something similar so it wouldn’t matter how long the password is. What this means, of course, is that they’re storing the passwords unhashed.
  • W3C has published a draft of its Web Cryptography API. When this is finalized and implemented it could help improve Web security. But it probably won’t because the usual people still won’t bother doing the right thing.
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Emacs Rocks! Episode 13

Posted on 2012-09-25 by jcs

Magnar Sveen is on a tear and has posted another Emacs Rocks! episode. This one is, to use a phrase Sveen might utter, mind-blowing. It’s a demonstration of his Emacs extension multiple-cursors. When I first saw this extension demonstrated in Sveen’s Oslo Web Rebels talk (that I discussed here) I was blown away by the seeming magic of it. Episode 13 gives a much more comprehensive demonstration and simply must be seen to be appreciated.

The really good news is that multiple-cursors is now available on Marmalade and Melpa. I’ve been using mark-multiple (also by Sveen) but disabled it after I downloaded multiple-cursors because the latter is essentially a superset of the former. Watch the demonstration and you’ll want to install it too.

I’ve just started using it but I’m already Addicted. As I say, watch the video and you’ll be an addict too. And if you haven’t already, watch the Web Rebels talk too—it’s fantastic.

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An Elisp Puzzle

Posted on 2012-09-24 by jcs

Xah Lee points to this interesting tweet The three S’s of SUCCESS by Gary Fredericks and asks for something similar in Elisp. Fredericks’ code is

(map (vec "SUCCESS") [0 5 6])

which certainly isn’t Elisp.

My first attempt at Elisp is

(mapcar (apply-partially #'aref "SUCCESS") '(0 5 6))

which does the trick but outputs the results as integers

(83 83 83)

because that’s how Emacs represents characters.

If we want to print out the actual S’s we need to wrap the above in some extra code

(mapcar #'char-to-string (mapcar (apply-partially #'aref "SUCCESS") '(0 5 6)))

which yields

("S" "S" "S")

What we really need here is something like the Common Lisp char function that outputs the actual characters but, of course, Emacs can only do this my making strings. On the other hand, CL lacks the nice currying function apply-partially so I don’t see a nice succinct solution in it either.

Update Noam has a much better solution in the comments.

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Common Lisp Type Hierarchy

Posted on 2012-09-23 by jcs

Greg Pfeil over at Techomatic has a nice chart of the Common Lisp Type Hierarchy. Technically, there’s no new information here, of course, but it is nice to have all the information in any easy to read diagram.

If you’re a Lisper, this diagram is worth a look. It makes the whole hierarchy visible in a simple and clear way.

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Emacs Rocks Episode 12

Posted on 2012-09-22 by jcs

Magnar Sveen has Episode 12 of Emacs Rocks up. This time it’s about editing HTML. As usual, Sveen demonstrates some nifty tricks to make editing easier. Some of them use standard Emacs functionality and others extensions that he has written.

My only complaint is that the video moves very fast and it’s sometimes hard to see what he’s doing without replaying it several times. That problem is mitigated to some extent by a listing on the episode page of all the commands that he’s using. The pacing problem notwithstanding, this episode, like the others, is outstanding. You may also want to pick up some of Sveen’s extensions. They are very useful; I already can’t live without some of them.

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The Vim Horror

Posted on 2012-09-21 by jcs

Via Xah Lee: The horror! The horror!

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What the…

Posted on 2012-09-20 by jcs

If you’re a Lisper here’s a surprising bit of Common Lisp arcana from Xach’s Common Lisp Tips. Did I mention that you really should subscribe?

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The Acme Editor

Posted on 2012-09-19 by jcs

Russ Cox has posted a video tour of the Acme editor. If I weren’t using (and extraordinarily happy with) Emacs, this is the editor I would be using. For a long time it was only available with Plan 9 but Cox missed it so much when he stopped working on Plan 9 that he ported it and much of the Plan 9 environment to Unix like systems (such as FreeBSD, Linux, and OS X). That port is available to all as Plan 9 from User Space.

The video is entertaining and well worth a look. Perhaps it will give you some ideas that you will want to port to Emacs.

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Have You Tured Today?

Posted on 2012-09-18 by jcs

Of course you have. Wait. What is turing? For reasons explained on his Web site, Don Knuth defines to ture as to use the Internet. Knuth asks that if you agree with this definition that you encourage its use via social networks.

I’m not sure if this will catch on but it does fulfill a need and is not offensive so I’d be just as happy if it did. If you agree, you should pass on the suggestion in whatever way you have.

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