Most of OpenGroupware.org is written in a language called Objective-C, or
in short, ObjC. ObjC is a very simple object oriented extension to ANSI-C
and features Smalltalk OO at ANSI-C portability and speed.
Using Objective-C you can tweak almost any aspect of OpenGroupware.org.
Some links to tutorials which are relevant if you want to start out
developing on OGo.
C Language Tutorial for Cocoa
Spanish: Objective-C Links
LinuxJournal: Objective-C: the More Flexible C++
Objective-C is Fun
by Adam Fedor
Writing GNUstep Makefiles
by Nicola Pero
More on GNUstep Makefiles
by Nicola Pero
Basic GNUstep Base Library Classes
by Nicola Pero
Hold Me, Use Me, Free Me
Memory Management in ObjC
by Don Yacktman
The Objective-C HomePage
The Objective-C Reference
Bundle up for a warm reception
by Don Yacktman
Accessor methods revisited
by Mmalcolm Crawford
Very simple rules for memory management
by Mmalcolm Crawford
Delegating Authority - Delegation and Notification
by Erik Buck
Categorically Speaking
by Howard Ship
