Nokia has just announced that Qt v4.5 is going to be available in LGPL form. This is a huge announcement, and is interesting from a number of perspectives, many of which aren't necessarily obvious at first glance.

I was a recent guest on Late Night Cocoa where I extolled the virtues of developing applications in high level languages like Python, especially if you wish to do cross-platform development. Nokia's announcement could be a game changer.

I love Cocoa and the new Python bindings that Apple has supplied. However, if you need to do things cross-platform, Qt is the best alternative. I have concluded, from my many experiments, that Qt is the only cross-platform toolkit that approaches the polish of Cocoa. And, RiverBank's excellent PyQt is a very natural binding for Python. And, best of all, Qt 4.5 on the Mac is built on Cocoa.

However, up until now there has been a problem. If you licensed Qt for use in a commercial app, you would be forbidden to directly expose Qt via a scripting language to your customers. This makes sense from a certain perspective because a development license for Qt can run up to $3k. If you offer scripting in your app, and your app costs less than a $3k, then you would be undercutting Nokia. And, you would be keeping all the money.

In other words, until now you would have been prohibited from using PyQt in your commercial application if you exposed a scripting API, even if you were willing to pay the licensing fees for Qt and PyQt. However, with the LGPL, you'll be able to link to the Qt libraries from a commercial app without a commercial license from Nokia.

If people realize the inherent value in using Qt with a scripting language like Python, this could open up a whole new avenue for low-cost, high-quality, cross platform development.