Synchronizing RDF data from files with the ARC triple store

Pete — Thu, 14 Feb 2008 17:35:38 +0000

I have been playing with the excellent ARC framework for a small legal information project (more on that soon). I am beginning to think that many RDF usage scenarios involve data in files (stored in a file system) combined with a triple store that preferrably should be kept in sync with the files. Inspired by Niklas Lindström’s Oort I wrote a small plugin to do that in ARC.

The plugin extends the ARC2_Store class with a sync_with_folder($path_to_folder) method. Here is the source code for the initial version if you want to play with it. Rename the file to ARC2_FilesystemSynchronizerPlugin.php ansd save in the ARC plugin folder.

By popular request, here is a simple usage example:

//Include ARC and configuration
include_once(‘path/to/arc/ARC2.php’);
include_once(‘path/to/arc/config.php’);

$store = ARC2::getComponent(‘FileSystemSynchronizerPlugin’, $config);
$store->sync_with_folder(“/root/path/to/file/store”);

Save the above code to a file called sync.php and run from the command line with php sync.php

Intricacies of PHP compared to Ruby

Pete — Tue, 01 Jan 2008 09:25:19 +0000

Via Tim Bray’s blog I found zestyping’s “Why PHP should never be taught”. In it he provides some interesting PHP code that will be difficult for beginners to understand.

$a = 0;
$b = "eggs";
$c = "spam";

yields:

a == b
b != c
a == c
a == d
b != d
c != d

(Please note that d hasn’t been defined). In the comments, people freak out and tell him that this behaviour is defined in the documentation. I guess that makes it even worse.

Trying the same thing in Ruby:

a = 0
b = "eggs"
c = "spam"

a == b
=> false

b == c
=> false

a == c
=> false

a == d
NameError: undefined local variable or method 'd' for main:Object from (irb):7

Peter Krantz » PHP

Synchronizing RDF data from files with the ARC triple store

Intricacies of PHP compared to Ruby