You could maybe do something with fs_usage, I'm not sure. Like I said before, the speed hit isn't even going to be noticeable by the end user, so I'm not sure why Rosyna is arguing this.

If you take a recursive function it's upper bound of running time is going to be dependent on how many possible possibilities there are. The application skinning functionality for ShapeShifter is going to be O(number of files being skinned), no matter how it's done. The longest possible running time is going to be the number of files being skinned. This is because at worst, ShapeShifter is going to have to look at the file being opened and compare it against every single file that it is interested in theming.

If Unsanity has found a way to make a recursive function where the number of iterations is dependent on some sort of scaling list, and make that run time constant, I have a friend who would be very interested in it. I also think they should talk to the Nobel Prize people.

Debating about Big O notation on a GUI forum seems kind of pointless to me. If you'd like to continue looking at Big O notation Rosyna see Google or email me at colin (at) whitemagiclabs.com.