Archive for May, 2006
Seven years ago, I wrote a two-player puzzle game in Python. I recently dug it up again and Matthias persuaded me to make a first release available here.
Both players sit at the same keyboard.
RULES
The object of the game is to take over all the other player’s
generators.
The board is made up of a grid of movable “tiles”. Each tile on the
board is one of three colours: red for the red player, blue for the
blue. One player moves using the arrow keys, the other using W, A, S,
and D. When a player moves, they swap places with a tile; thus by
moving about the board they move the tiles around, as in Sam Loyd’s
“15 puzzle”.
Certain tiles are “generators”. The neutral-coloured generators do
nothing. The red and blue generators periodically produce “pulses” of
their own colour. These pulses travel along the pipelines on the
board. When they hit a neutral-coloured tile or a tile of their own
colour, they set the tile to their own colour and carry on; when they
hit a tile of another colour they stop. If they hit a blank tile, a
generator, or a player, they always stop. When a pulse stops, the
generator that produced it makes another pulse (unless it’s turned
neutral in the meantime).
Certain tiles slow players down. If a player moves through a tile of
another colour, or a tile containing a pulse, they will be frozen in
place for a second before they can make another move. Players cannot
move through each other.
If a player has no generators of their colour and no pulses of their
colour on the board, then no tiles can ever be changed to their colour
again and they lose.
Certain tiles are placed deterministically; the rest are random but
symmetrical. Press “r” a few times to restart the game and see what
sort of board positions are possible.
“p” pauses the game. “q” quits.
TACTICS
Thus far I’m the only person who’s ever really learned to play this,
so I don’t really know how to play it well, but a few things are worth
pointing out. But racing to turn as many generators as possible your
colour at the start of the game will fill the board with tiles of your
colour, and thus slow your opponent down; you can then work on trying
to turn their generators to your side.
Play with it on your own for a bit before trying against an opponent.
FUTURE
I don’t know if I’ll ever work on this again. If I do, the two
obvious improvements to make would be a port to SDL, and network play.
May 31st, 2006
Paul Crowley
How about making a non-alternating knot with projection of minimal crossing number (which, incidentally, is eight)?
(Thanks to David Snyder who told us this.)
May 30th, 2006
francis
The folks at HackNDev have managed to port Linux to the Tungsten T3! It’s primitive at the moment - no support for the off button, slightly flaky SD card driver - but boots easily enough to a graphical environment you can actually use. The one (expected) downside is that it wipes your RAM, so you need to hard-reset to get back to PalmOS, and restore from backup to get your PalmOS information back.
Thanks to the folks in #hackndev on irc.freenode.net for helping me get Linux booting on my T3.
I’ll be interested to follow the work on the power-button support and other hardware-level features: I’d eventually like to get Squeak running.
May 24th, 2006
tonyg
As part of a recent development project, we’ve assembled pieces from SISCweb, SSAX and SXPath, and some of our own code to build a simple web-development framework we’ve tentatively named Icing.
Icing, so far, consists of:
a simple bean-like layer atop raw SQL, with an S-expression based SQL syntax and objects representing table rows;
a small library (not quite the same as SISCweb’s approach) to allow pattern-matching on the URLs of incoming requests, and to allow attaching handlers to matched URLs;
libraries for using JavaMail to construct and send arbitrary MIME multipart message parts and for using BouncyCastle’s PGP implementation with JavaMail to build PGP MIME email bodies and attachments; and
a XSLT-template-based Model-View-Controller-plus-Workflow framework for structuring applications. HTML templates (with special attributes and with optional embedded XSLT instructions) form the View; Scheme code forms the Controller; the DB layer referred to above forms the core of the Model; and SISCweb’s support for continuation-based web programming forms the Workflow.
The software is still being hammered into shape; we’re currently in the process of documenting it, packaging it conveniently for use in other applications, and deciding how we want to release it — it could be released as a thing-in-itself, bundling together a collection of third-party libraries, or we could instead take Icing to pieces, and fold some of the parts back into SISCweb (if SISCweb’s author, Alessandro Colomba, approves, of course).
I’ve made the slides from the presentation on Icing I gave last week available. They’re the only real documentation the code has at present, but ought to give a feel for the kind of approach we’re taking with it.
May 22nd, 2006
tonyg
There was quite a lot of excitement about Microsoft’s Concurrency and
Coordination Runtime
(CCR) when it
surfaced back in December. Recently several people asked me my opinion
about this technology.
According to the above link the CCR
is super cool stuff and represents a really innovative
approach to making managed threaded programming more readily
understandable and predictable.
Does the CCR live up to this promise? I don’t think so.
Continue Reading May 17th, 2006
matthias
I bought a Proliant DL380 on eBay for £27. Its got a couple of 866MHz Pentium 3s, 512Mb of RAM and two very fast 18Gb SCSI drives. It’s a first generation, which is sometimes called G1, but mostly just omits the generation in documentation. That makes it annoyingly difficult to Google for.
I couldn’t get Linux (Debian testing) to recognise the RAID controller. If I loaded cpqarray, the device seemed to get detected, but could not then detect any drives. I noticed an IDE connector on the mother board, so I figured I’d just replace the SCSI disks with a couple of cheap IDE disks. So I ordered them, and they duly arrived.
The first time I booted, they didn’t get detected by Linux, and access to the CD drive slowed down a lot. At this point I decided I’d have to get the setup CD (there is no BIOS configuration tool in the BIOS itself). You can get that here. I was a bit perturbed to find the BIOS help said that IDE fixed disks are unsupported. I guess I should have read the manual first.
Anyway, I had them set up as master and slave, and changed them to cable sensing, just in case Linux might detect them anyway. This had the result that I got /dev/hda with 3 cylinders and a correctly detected /dev/hdb. Unfortunately the performance problem was even worse this time.
I decided to try and work out if the RAID controller could be disabled, so I could see the SCSI disks under linux. I couldn’t just move the disks from the RAID controller to the non-raid controller, since they have 80pin SCSI connectors. There is a dip switch block, which I can’t find any documentation for. I decided not to mess with that. Instead, I removed a little daughter card from over near the SCSI connectors. It might be a mini-PCI card. Anyway, that turns out to be the RAID controller. With it removed, Linux detects the SCSI card it was using, and I am left with two SCSI drives I can use software RAID on.
Unfortunately, that’s less disk space than I need, so I still need to figure out how to get my IDE drives to work. At least it will boot debian now. I guess I’ll use a PCI IDE adaptor. Maybe even an IDE RAID controller.
If anyone knows what the DIP switches on the MB do, I’d be delighted to know.
May 16th, 2006
david
Today, attempting to port SPrevayler to Squeak 3.9, I ran into a problem with the FilePlugin. It turns out the problem is already covered by a test case in the image, and that the test case is currently failing, at least on Linux on the versions of the VM I tried (3.7-7, 3.9-7, and svn trunk).
The problem is that FilePlugin is caching the DIR* for the directory that was just deleted, and deleting the directory doesn’t invalidate the DIR* cache. Adding a check against lastPathValid and lastPath in dir_Delete solves the problem. Hopefully the fix will be included in mainline builds soon.
(The bug report I filed is at http://bugs.impara.de/view.php?id=3649.)
May 16th, 2006
tonyg
Some Unix command line tools display text in colour, if you run them
in the right kind of terminal, of which the Emacs shell isn’t
one. So far this had not really bothered me since in most cases the
colours do not convey all that much information. However, recently I
was playing with Maude, which colours
terms for
debugging purposes. There is no easy alternative for getting hold of
the same information.
A few minutes of googling and experimenting produced the magic Emacs
command
(require 'ansi-color)
followed by customisation of the ansi-color-for-comint-mode variable
(setting it to t) or calling (ansi-color-for-comint-mode-on). This
applies across all comint sessions, not just shell sessions, so it
also affects things like the interactive Maude mode.
Under Emacs one can go further with M-x ansi-term, which creates a
fully-fledged ansi terminal inside an emacs buffer. Finally we can run
Emacs inside Emacs inside Emacs …! Ansi-term is not available for
XEmacs, probably because it is some ghastly hack.
May 10th, 2006
matthias
I’ve been using Squeak’s BookMorph to assemble presentation materials
recently, but there’s been no way to export the presentation for the
benefit of those without a Smalltalk image - until now. I just
implemented a trivial little method on BookMorph that exports all its
pages to PNG files, and writes a small HTML index file.
Here’s one I prepared earlier:
http://www.lshift.net/~tonyg/cake-presentation/PresentationBook.html
(the presentation itself isn’t done, and won’t mean much outside LShift at the moment, but it’s enough to demo the idea.)
Here’s the method I wrote:
exportPagesAsPng
| fileName indexPageStream |
'Exporting ', pages size printString, ' pages to PNG'
displayProgressAt: Sensor cursorPoint
from: 1 to: pages size
during: [:progressSetter |
pages doWithIndex: [:page :i |
progressSetter value: i.
fileName := self externalName, '_',
(i printStringLength: 3 padded: true), '.png'.
PNGReadWriter putForm: page imageForm onFileNamed: fileName.]].
indexPageStream _ FileStream newFileNamed: self externalName, '.html'.
indexPageStream nextPutAll: '<html>...</html>'.
"html and javascript elided - have a look at the example."
indexPageStream close.
May 10th, 2006
tonyg
We were getting a large volume of comment-spam, so I’ve added a wee Turing test to the comment form. I hope it doesn’t put anyone out.
It certainly inconvenienced me—the plugin needs a graphics extension for PHP. “No problem,” I thought, “I’ll just apt-get install the package for it.” But apt-get went on a rampage, (seemingly) removing the entire WordPress installation and insisting on installing new versions of everything from gcc up. As a final insult, it not only failed to configure PHP to use the extension, it disabled the database extension!
Yes, I accept that it was probably my misuse of apt-get that provoked it. I’ll be sticking to Gentoo for myself, all the same.
May 10th, 2006
mikeb
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