Kenny Tilton wrote:
Cells II seems to be OK, and is back at work running Cello as well as passing its regression tests. It will be released when I figure out whether to put everything up on the Cells or Cello project. I plan from here out to focus more on developing a commercial title (using Cello) than on porting Cello. This may mean I will not even look at OS X until the commercial title is ready to go and I want the OS X version (I will). This also means I want a very simple way to share my ongoing work on Cello/Cells and the easiest will be to have one cvs repository I update periodically.
Anyway, for now, here is the spec which guided the Cells II rewrite:
Suppose the application is at some steady state S in which all Cells (slots of instances) are either inputs (what I used to call c-variable) or have been computed from other Cells.
Now the application polls a socket or OS event stream and gets a new input, which leads to some cell X being assigned a new value.
Suppose also the new value for X is different from the prior value (according to a user-definable test). We now have not just a write operation but also a semantically meaningful change to X, so we also consider a new state S+ to have been established, with X being the only Cell to have reached state S+.
Now suppose there exists some cell A which depends only on cell B which depends only on X. Suppose also that when cell B gets recomputed to reach state S+, the change test for B's new value indicates "no change". Let us then say B is dependent on the change to X but /unaffected/ by it.
should be "A and B are dependent on but unaffected by the change to X".
kt