Xcode may or may not be pre-installed on your Mac OS X system. To find out if you already have it, open the Finder and look for it in the ''Developer'' subfolder of the ''Applications'' folder. If the ''Developer'' folder does not exist, or does not contain Xcode then you will need to install it.
The best way to obtain Xcode is to download it from the Apple web site. It can also be installed from the Developer Tools installation disk if you happen to have one, but most Mac systems do not ship with this. The URL to download Xcode is [http://developer.apple.com/technology/xcode.html http://developer.apple.com/technology/xcode.html]. There are two forms of Xcode, one for developing both Mac OS X and iPhone applications and the other solely for developing Mac OS X applications. In order to download Xcode, you will need either a Registered iPhone Developer account (in the case of the iphone Xcode) or an ADC membership (in the case of the Mac OS X Xcode). Fortunately, both of these memberships are free and can be activated using your existing Apple account (for example the one you use to buy music on iTunes).
Exception encountered, of type "Error"
[6f3a79f9] /index.php/Special:MobileDiff/14240 Error from line 434 of /home/techotopia/includes/diff/DairikiDiff.php: Call to undefined function each()
Backtrace:
#0 /home/techotopia/includes/diff/DairikiDiff.php(544): DiffEngine->diag()
#1 /home/techotopia/includes/diff/DairikiDiff.php(344): DiffEngine->compareSeq()
#2 /home/techotopia/includes/diff/DairikiDiff.php(227): DiffEngine->diffLocal()
#3 /home/techotopia/includes/diff/DairikiDiff.php(721): DiffEngine->diff()
#4 /home/techotopia/includes/diff/DairikiDiff.php(859): Diff->__construct()
#5 /home/techotopia/includes/diff/DairikiDiff.php(980): MappedDiff->__construct()
#6 /home/techotopia/extensions/MobileFrontend/includes/diff/InlineDiffFormatter.php(99): WordLevelDiff->__construct()
#7 /home/techotopia/includes/diff/DiffFormatter.php(140): InlineDiffFormatter->changed()
#8 /home/techotopia/includes/diff/DiffFormatter.php(82): DiffFormatter->block()
#9 /home/techotopia/extensions/MobileFrontend/includes/diff/InlineDifferenceEngine.php(117): DiffFormatter->format()
#10 /home/techotopia/includes/diff/DifferenceEngine.php(797): InlineDifferenceEngine->generateTextDiffBody()
#11 /home/techotopia/includes/diff/DifferenceEngine.php(728): DifferenceEngine->generateContentDiffBody()
#12 /home/techotopia/extensions/MobileFrontend/includes/specials/SpecialMobileDiff.php(241): DifferenceEngine->getDiffBody()
#13 /home/techotopia/extensions/MobileFrontend/includes/specials/SpecialMobileDiff.php(135): SpecialMobileDiff->showDiff()
#14 /home/techotopia/extensions/MobileFrontend/includes/specials/MobileSpecialPage.php(53): SpecialMobileDiff->executeWhenAvailable()
#15 /home/techotopia/includes/specialpage/SpecialPage.php(384): MobileSpecialPage->execute()
#16 /home/techotopia/includes/specialpage/SpecialPageFactory.php(553): SpecialPage->run()
#17 /home/techotopia/includes/MediaWiki.php(281): SpecialPageFactory::executePath()
#18 /home/techotopia/includes/MediaWiki.php(714): MediaWiki->performRequest()
#19 /home/techotopia/includes/MediaWiki.php(508): MediaWiki->main()
#20 /home/techotopia/index.php(41): MediaWiki->run()
#21 {main}