Thursday, March 13, 2008

Cocoa development, using a Lisp bridge

Let's get a bit away from my PhD for a while. In my spare time, I've been looking at some graphic libraries to make some applications. In the past I've looked for Operating System portability for those apps. I've also delved into the Web world for interfaces. Right now, I've settled for making pretty looking gui's. If you add my new acquisition - a Macbook Pro, my first mac ever! - and I obviously had to try to make a MacOS Cocoa application. They're fashion, they're usable, they mingle with the rest of the desktop manager, and I was just tempted to try to use Lisp to make something like it.

Fortunately, this wasn't so hard, has OpenMCL has a great step by step tutorial (to be taken with a few glasses of water and with the Cocoa / Interface Builder tutorials made available by Apple). This tutorial has detailed instructions of how one can build the Interface with the WYSIWYG tool that comes with Xcode. Then it tells you how to setup the connection points between the interface and the application code. These are called outlets, for the variables in the code that represent a given object (so that you may, for instance, retrieve the text in a text field) and actions, for the functions that are called when something happens in the interface (e.g., user click in a button). After creating the necessary objects (basically you must make them belong to a specific metaclass in order for them to be exported as an ObjectiveC class), all you have to do is call a function that binds together the compiled code, the Interface files (in the nib format) and places a nice application bundle in the directory of your choice. It can't get any easier, you think. And yes, you may code interface changes in you lisp code. But it's extremely easier to follow in Interface Builder guidelines and helpers... You just can't go wrong!

You may find the tutorial at the OpenMCL wiki: http://trac.clozure.com/openmcl/wiki/AppleCurrencyConverter

2 comments:

Mike said...

Thanks for the pointer!

Edgar Gonçalves said...

@Mike You're welcome! Feel free to tell your tale about it. What you've accomplished, the perils you had to go through, the dragons you slayed and the swords you use. This should be widely discussed, I see too little cocoa / lisp blog posts around!