http://www.brool.com brool \brool\ (n.) : a low roar; a deep murmur or humming Wed, 03 Mar 2010 15:47:40 +0000 http://backend.userland.com/rss092 en Okay, Lein really does make stuff pretty easy. Rather than wrestling with eleventybillion classpaths, just install Lein. Create a new project directory with lein new mydirectory Change the project.clj file that is autogenerated with: defproject mydirectory "1.0.0-SNAPSHOT" :description "FIXME: write" :dependencies [[org.clojure/clojure "1.1.0-alpha-SNAPSHOT"] [org.clojure/clojure-contrib "1.0-SNAPSHOT"] ... http://www.brool.com/index.php/setting-up-incanter-and-mysql I don't need to tether through my iPhone — I always seem to be near a hotspot — but nonetheless I thought that spending 10 minutes to set it up was worth it, because when you need tethering, you really need tethering. If you're willing to drop $10 bucks ... http://www.brool.com/index.php/tethering-an-iphone-with-ssh-and-windows-7 I've had an Asus EEE 1000h ever since they came out, but it was getting to be time to upgrade it -- it was not a bad little machine, but the Atom processor was a bit underpowered, and that damnable right shift key always did bug me. I picked ... http://www.brool.com/index.php/acer-1410-mini-review Warning: a very rambling article; less a solid proposal than me just exploring an idea that may lead to a dead end in a week or two after I've thought about it. I really enjoy Clojure. Everything seems so well thought out and well designed; in a lot of ways it ... http://www.brool.com/index.php/a-modest-proposal The proxy function makes it easy for Clojure to interface with the Java layer, but I was dealing with an interface (the AIM Java API) that had an punitive number of things that needed to be overridden... [source lang="java"] public void OnIdleStateChange(AccSession arg0, int arg1) { } public void OnInstanceChange(AccSession arg0, AccInstance arg1, AccInstance ... http://www.brool.com/index.php/snippet-automatic-proxy-creation-in-clojure Updated: Note that this is available as a clojars module. Clojure code density seems to be pretty good. There are a fair number of convenient shortforms in the language; for example, associative datatypes all act as a function — so given a hash map you can reference it with (my-hashmap ... http://www.brool.com/index.php/pattern-matching-in-clojure Clojure isn't the fastest functional lanuage -- that title seems to go to Haskell these days, at least for the stuff that I do -- but it nonetheless is usually fast enough. It's a dynamic language, so is perhaps cursed to be somewhat slower always, but nonetheless for the ... http://www.brool.com/index.php/aset-is-faster-than-aset-int I've been playing with Tokyo Cabinet and Clojure for a bit, and while I will go on about both of them in another blog post (or not), I have to mention that Clojure is such a well designed language that it's a pleasure to play with. It has much ... http://www.brool.com/index.php/tokyo-cabinet-api-for-clojure I've found Wordpress to be pretty decent, aside from the security updates every other week, but for me writing is a very spur of the moment thing; I prefer to be able to go into Emacs and just immediately type anything without having to log into my blog, create ... http://www.brool.com/index.php/posting-to-wordpress-from-git (This is almost too stupid to post, but on the off chance that someone actually needs something like this...) I needed to interface with a bunch of data that had PHP wrapper classes, and needed a quick way of being able to interface with PHP from Python. (At this ... http://www.brool.com/index.php/hacks-python-calling-php I was switching between git repositories the other day, and managed to do a "git reset --hard HEAD^" in the wrong repository. Which wasn't bad, since I had most of the files already open in Emacs... but then Emacs calmly told me that it was re-reading the files from ... http://www.brool.com/index.php/recovering-from-a-hard-reset-in-git Let's say that you really, really want some notion of objected oriented programming. So let's make a class that represents a name, and some simple method calls on it: [source] data S = S { name :: String } deriving (Show) firstname s = (words (name s))!!0 lastname s = (words (name ... http://www.brool.com/index.php/stupid-haskell-tricks A small snippet of code that demonstrates calling into a Wordpress XML-RPC server with Haskell and HaxR. [source] import qualified Data.Map as Map import Data.Maybe import Network.XmlRpc.Client import Network.XmlRpc.Internals server = "http://yourserver.wordpress.com/xmlrpc.php" -- extract multiple posts from the XML response extract :: Value -> [Map String Value] extract xmlresp = let ValueArray rs = xmlresp ... http://www.brool.com/index.php/haskell-to-wordpress-snippet Ran into another interesting performance problem while converting a small test program over to Haskell. Let's say that you want to walk through every line of a text file, collate character frequencies, and return anything that maps to a particular frequency. For purposes of explanation we'll do something really ... http://www.brool.com/index.php/haskell-performance-array-creation I was trying to track down some issues with some text processing programs that I was writing in Haskell, and ran into an interesting problem. I made one small change and my program ended up being 5 times slower, and I had to backtrack to try and find out ... http://www.brool.com/index.php/haskell-performance-lowercase For comparison purposes, I was rewriting the silly little e-mail digest program in Haskell, using Python libraries for the IMAP interface (it's available on Github). It's hard to beat Python's amazing collection of libraries. Cabal / hackage isn't bad, but it doesn't yet approach Python's "batteries included" philosophy and ... http://www.brool.com/index.php/using-missingpy I will be updating this as I go... but see also the Wikipedia page on string functions in various languages. Joining a string list [source] -- Python: ",".join(lst) -- either... import Data.List intercalate "," lst -- or... import Data.List concat (intersperse "," lst) [/source] Splitting on a string [source] -- a.split(ss) -- You might need to get Data.List.Split from Cabal import Data.List.Split splitOn ss ... http://www.brool.com/index.php/python-to-haskell-string-functions I would like Haskell better if it didn't do its best to make me feel stupid. Tasks that are easy in other languages, such, say, maintaining some state or generating a random number, become difficult. After banging my head on the State monad I finally arrived at a ... http://www.brool.com/index.php/state-monads-in-haskell My 500GB backup drive started making horrible, horrible noises when spinning up, akin to a lawnmower trying to mow a rock, so I decided that it was time get another backup drive so that I would be safe. I picked up another drive at Fry's (not a Maxtor this ... http://www.brool.com/index.php/recovering-a-trashed-ext3-system My Asus EEE 1000h had this really irritating but intermittent bug -- it would hang occasionally when I was using it. The keyboard was dead, but a) mouse clicks would still work, and b) I could Ctrl-Alt-Backspace to restart X or Ctrl-Alt-Fn to go to a terminal. So, ... http://www.brool.com/index.php/mysteriously-hanging-ubuntu