RubyCocoa is a promising technology for those of us who like ruby and have always wanted to build OSX applications but never wanted to learn Objective-C. Now that the framework is included in Leopard (OSX:10.5), I have started building my own application using rubycocoa. Below are the top 5 things I wish I had known when I started out, so I have compiled them to save you some time.
1) Get familiar with the rubycocoa and apple developer websites.
www.rubycocoa.com is the most complete website for information regarding the framework. Before you get to far into your application make sure to read through some of the excellent tutorials and comments. There is a wealth of information on this site, and most of my simplier problems were resolved pretty quickly by checking out some of the examples.
The cocoa development is a great place for information regarding the cocoa language. While all the examples are written in Objective-C the examples will point you in the right direction and the tutorials are very complete. Furthermore since this is apple, this is the place to look for information when you are trying to figure out what is wrong.
2) Get the API's
The Cocoa API's are included with XCode so you won't have to worry about those, but rubycocoa api's are not included with Leopard. The rubycocoa web site will tell you the api is installed in /Developer/Documentation/RubyCocoa/Frameworks. This assumes that you have built the project from source and have installed the documentation locally. Before you get into actual coding of your application I would highly suggest building a local version of the source just to have the API. Also if you are building the API from the source, make sure to build the examples as well. These are the "ruby" versions of the Objective-C tutorials included with XCode.
When looking through the cocoa API's get used to checking out the ruby ones as well. Compare the methods and you will quickly see how the wrapper is working it's magic. In no time you will be able to read the Objective-C code and figure out what the rubycocoa equivalent is.
3) Hit The Books
The book Cocoa Programming For Mac OSX Second Edition is a great book for beginners looking to jump into OSX development. While this book is written for Objective-C and XCode 2.0, it provides an excellent introduction into cocoa programming, and servers as a good reference for when you want to venture into your own ideas. Rubycocoa is just the language, and without the understanding of how to build a cocoa application you will get frustrated very quickly.
4) Build The Tutorials
XCode and Interface builder, along with the excellent tutorials on the net will allow you to start fast. You can get an application up and running pretty quickly without really knowing how things are working on the backend and if you are like me, then you will jump right into your application, draw your interface and then get stuck with the details of how to make things happen. Take some time to build the sample applications and really look at the tutorials.
5) Join The Lists
The apple developer network is extensive, and has plenty of great people willing to help you out. Most of the development lists focus on Objective-C techniques and code, but once you get used to how the rubycocoa wrapper works then these mailing lists will be a great source of information for you.
Lastly I just want to point out that building an OSX application is very unlike any of the development you have done on other platforms. While the rubycocoa framework is a great alternative for those of use who don't want to learn Objective-C it is only a small portion of what it takes to build your application. Take the time to learn the cocoa fundamentals and the tools, they will come in handy when you are stuck later down the line.