Mhm, Baike has a point there. I also think that the add-ons are really well done and will help users learn a lot about Sparrow, Shilo! You're doing a great job with them =)
As I said, some of those features will be added to Sparrow anyway on the long run.
But even if you provide support for the add-ons, it might turn out difficult to find out which code users are talking about when they post a question/problem in the forum.
I'm sure not all of them will remember to add a note that they are using modified classes -- or perhaps they are not even aware of it, because they are using a standard Sparrow class on the surface, which might be backed up somewhere internally by a modified class.
Perhaps there's a compromise that would make this easier. You could split your tutorials up in 2 parts:
a) subclasses and extensions to existing classes that can simply be dropped into an application (like the SPLine class you've just created!)
b) extensions that modify the source code directly.
Classes of a) are not a problem at all, because users will be aware that they are using them -- perhaps by giving them a custom prefix (e.g. SH for Shilo 🙂 ).
And in front of the b) part of your tutorials, you could write a big disclaimer, telling the users that they are primarily provided as a starting point for learning the internals of Sparrow, and that they should use them with care. (Plus, always mentioning the fact that they are using them when they ask for help with a problem in the forum.)
Anybody could use them just like before, they'd just be aware that should take care.
What do you think of that?