I was talking today about ways of extending a code model (like, the one inside Pharo that represents my packages, classes, and methods), and realized that I need to publicize some patterns that Daniel Vanisencher and I worked out some years ago when we were trying to separate the computation of the required-methods property (needed for traits) from the particular browser that one might use to look at it. The key idea behind these patterns is to take the work of recomputing some property of the model out of the browser, so that we do not get complaints that "Pharo is too slow". The paper is at http://web.cecs.pdx.edu/~black/publications/ModelExtensions.pdf It's quite long, but I think that it is easy to read. A version has been accepted by the new Springer Journal "LNCS Transactions on Pattern Languages of Programming", if it ever appears. ____________________________ Prof. Andrew P. Black Department of Computer Science Portland State University Oregon, USA http://www.cs.pdx.edu/~black Telephone: +1 503 725 2411