I was able to complete a proof-of-concept value engine with just 9 lines of Prolog, minus comments.

The next step, of course, was to find a way to allow Python to call Prolog predicates. As I was using SWI-Prolog, I downloaded PySWIP.

PySWIP is a simple gateway between the SWI-Prolog interpreter and Python. The project was briefly orphaned for a while and the project’s author is actively looking for another developer to take the reins, so I can’t recommend this as an enterprise-grade solution. However, it seemed that for my purposes it would work just fine.

PySWIP did not work right out of the box. I had SWI-Prolog 5.10.4 installed on my machine and the latest version that PySWIP supported at the time was 5.6.34. Running

from pyswip import Prolog

resulted in

libpl (shared) not found. Possible reasons:
1) SWI-Prolog not installed as a shared library. Install SWI-Prolog (5.6.34 works just fine)

Fortunately the fix was easy. After some Googling I surmised that the issue stemmed from the fact that libpl.dll had been renamed to swipl.dll in the versions after 5.6.34. Navigating to C:\Program Files\pl\bin and making a copy of swipl.dll named libpl.dll did the trick.

Here’s a little example of using an external Prolog program in Python.

from pyswip import Prolog

prolog = Prolog()

prolog.consult("appraise.pl")

# A couple preliminary assertions.
prolog.assertz("value(banana, 1 rdiv 4, bitcoin)")
prolog.assertz("value(bitcoin, 1 rdiv 30, namecoin)")
prolog.assertz("value(apple, 3 rdiv 4, banana)")
prolog.assertz("value(orange, 1 rdiv 5, apple)")

# Now, how much is an orange worth in bitcoins?
result = prolog.query("appraise_float(orange, Price, bitcoin)").next()
print "An orange is worth %s bitcoins." % result["Price"]

# And how much is a bitcoin worth in apples?
result = prolog.query("appraise_float(bitcoin, Price, apple)").next()
print "A bitcoin is worth %s apples." % result["Price"]

Running this results in

An orange is worth 0.0375 bitcoins.
A bitcoin is worth 5.33333333333 apples.


Next up: SWI-Prolog/MySQL integration.

This is one of the worst-written articles about Bitcoin I’ve read so far. Certainly not worthy of your publication’s name. If you don’t understand something, don’t write about it. :-p

Your description of mining is so broken I’m not even going to try to fix it. Just do some more reading of low-level descriptions until you understand how very wrong your description of miners as “decoders” is.

“…it’s a massive experiment in group trust.”
Bitcoin is far from an experiment in group trust. It’s guiding principle is *distrust* of everything but the copy of the block chain residing on your own hard drive. Your statement seems to find its roots in your ignorance of the network’s mechanics.

“That’s a crazy amount of money to have stolen…”
Yep, that’s a lot of money to have stolen. The moral of the story is that if you have over a quarter of a million dollars worth of bitcoins sitting on your hard drive, *take some steps to secure them!* This is new ground for most people, but honestly it’s nothing that can’t be learned. To help the everyman, wallets will likely be encrypted and password protected in future versions of the Bitcoin client.

“Bitcoin is a libertarian’s dream come true…”
Not just a dream come true for libertarians. Also a dream come true for anyone who has ever pined for a convenient, politically neutral international currency, or an easy, cheap way of engaging in micro-transactions.

“So far, you can’t buy anything with bitcoins that you couldn’t purchase more easily with cash or a credit card.”
Aside from anything your government or credit card processor (assuming the vendor isn’t close enough for a physical cash transaction) doesn’t want you buying, that is. Most American citizens probably won’t care much about this one, save for all the folks who’ve had their PayPal accounts frozen at one point or another, or all those folks who support privately embargoed organizations like Wikileaks.

“…major exchanges like MtGox have fallen to hackers.”
The theft of $1,000 USD due to a *financial auditor’s* gaffe is hardly grounds for declaring Mt. Gox “fallen to hackers.” Also, can you point out to me one other exchange that has been similarly compromised? Because you’re using the plural, which implies there was more than one. Oh, there wasn’t? You mean you got your facts wrong *again?* Oh snap! :-p

“…the system presents a huge opportunity for big fish to take advantage of the Internet everyman.”
You’re right, the central banking system is WAY better. Those bankers are so honest and adept at managing our money! They would NEVER take bonuses using taxpayer money right after tanking the global economy. SO much fairer.

Should I beat you over the head with that one some more, or do you get it? :-p

“…Bitcoin won’t work because it accrues such a huge advantage to people who can bring the most computing power to bear on clearing transactions.”
You mean kinda like credit card companies? Herp derp.

” If any single person or group controlled a majority of computing power in the network…”
…they could have hacked your bank account a long time ago.

“It’s hard to trust a monetary system concocted and managed by anonymous hackers…”
Not really managed by them. If anyone deviates from the network’s protocol, they isolate themselves from the network. The official client gets pretty features added to it every once in a while by a guy named Gavin Andresen and five other developers, of whom only Satoshi is anonymous, to help out herp derps like yourself, but the essential elements never change. Although there *is* a continuous stream of essentially anonymous code auditors who spend their spare time reading the client’s source code on the project’s Github page. Perhaps those were the “anonymous hackers” you’re talking about?

Or maybe it’s the guys running Mt. Gox. You know, the same ones whose security was compromised because they were trying to comply with government regulations and the freaking financial auditor ended up having a freaking virus on his system. Those guys are ano– oh wait, it’s run by K.K. Tibanne Co, a totally legitimate Japanese company.

To be fair, there are a lot of tiny garage startups that make up a good portion of the rest of the Bitcoin economy. I’d say that’s a good thing, though: I’ve never heard anyone complain about an economy having too many startups, or too much innovation, or too many opportunities. It’s ultimately an indication of the innovation and further democratization of the global economy that Bitcoin encourages.

“Bitcoin still offers a glimpse of a future in which the dollar is digitized…”
Oh, cool. So right after complaining about the pitfalls of a digital currency (“that’s a crazy amount of money to have stolen by someone essentially copying a file from your hard drive,” remember?) you’re then going to advocate a system that not only has THOSE pitfalls, but also the pitfalls of our current centralized banking system. Awesome. Well done. Herp to the friggin’ derp.

I was thinking about the shortage of programmers and tech workers and the shortage of most other kinds of employment these days. It seems to me that if good technical education were more accessible, a lot of people would be a lot better off.

So why not create a system to automate the education of people in programming? That would be the easiest: teaching people how to program automatically. Just set up online lessons with live teachers at first. Have an “ideal” solution for each assignment. Let the teacher grade projects by hand at first.

As the teacher teaches and grades, let there be an algorithm monitoring and recording all the questions and answers students ask during and after lectures. Let it also record the errors made in assignments and the teacher’s notes when corrections are made. Let the algorithm suggest responses to the teacher based on past answers given. Let students directly question the algorithm for information given in response to questions during and after lessons, and for questions regarding assignments they’ve already completed.

Eventually the algorithm would be able to take over the teaching of most of the classes. Students should be encouraged to help each other after each lesson as well, to answer questions the algorithm could not. These too could be used to enhance the algorithm, though they would need to be screened for appropriateness.

The project should be supported by donations and volunteers. Those who graduate from the program in particular should be encouraged to help the new students that come after them. This could mean participating in after-lesson talks or simply responding to questions the algorithm can’t answer yet.

I’m starting up the first bits of the Lifestream project. To keep from annoying people too much, I’m relegating it all to certain channels. The first channel is up:

http://twitter.com/ryanslifestream

Check it out.

Ciao!

http://www.engadget.com/2010/04/29/microsoft-confirms-kills-courier-in-one-fell-swoop/

This means that part of my plan for lifestreaming is no more. Still, I’m pretty sure I can find a way to work around it…

More news to come… sometime.

I was trying to save an HTTP_Client object in a PHP session so that it would maintain its session data as it got moved from page to page. The idea was to log into a website with it and then go to another page where it would be used by various PHP scripts called by AJAX to perform tasks on the website I’d logged into. The only problem: I was getting logged out of the ‘site every time I left the script which logged me in. Somehow the HTTP_Client’s session data was being lost simply by my storing it in $_SESSION.

I made sure I was serializing and unserializing:

$_SESSION['client'] = serialize($client);
...
$client = unserialize($_SESSION['client']);

Still nothing. I scoured the Internet for people who were having similar problems. The only thing anybody could tell me was “are you remembering to serialize and unserialize?” I scoured the pitifully scant documentation on pear.php.net, trying to glean some shred of insight.

Still nothing.

So I decided to brute force the thing and trace the HTTP_Client’s code by hand. After mangling my beautiful PEAR classes with debug code, I noticed line 78 of CookieManager.php:

function HTTP_Client_CookieManager($serializeSession = false)

“Wait, a minute,” I thought, “you’ve got to be kidding me.” I changed that sucker to:

function HTTP_Client_CookieManager($serializeSession = true)

And it worked!

Now before you go hacking your PEAR modules, here’s the *right* way to do it:

$manager = new HTTP_Client_CookieManager(true);
$client = new HTTP_Client(null, null, $manager);

You can keep updated on my adventures as we plan this thing out and finally carry it through to execution at http://shoestringtour.blogspot.com