Can't we take advantage of inheritance for this issue? I don't know how far that can go, though, I'm not a programmer...
Thanks Maurizio On Sep 28, 9:40 am, William Stein <wst...@gmail.com> wrote: > On Mon, Sep 28, 2009 at 12:11 AM, Maurizio <maurizio.gran...@gmail.com> wrote: > > > First of all, thank you for the example! > > >> I'm pretty sure it is impossible to decide whether a cells output depends > >> on the > >> value of a given variable. You could get it write some of the time by > >> seeing > >> if the variable appears, but given the dynamic nature of Python it is > >> impossible to > >> decide in general. > > > What about the preparser? Can't we use it to recognize whether any > > variable belonging to the "live" list appear in the lines of the > > current cell? Then, it could just automatically append the "depend" > > attribute to the cell id. > > Sure, one could do that using the preparser. Unfortunately that > wouldn't really work because one cell can easily depend on the > variable x without the letter x explicitly appearing anywhere in the > cell. For example, suppose I define a function: > > def foo(): > print x > > in one cell, then put > > print foo() > > in another cell. The cell with "print foo()" in it depends on the > value of x, but x is not mentioned explicitly anywhere in that cell. > > > > > > >> That said, if you were allowed to tag a cell as depending, then this is > >> easy to > >> implement. I've even made an implementation of this in the current > >> notebook: > > >>http://sagenb.org/home/pub/905/ > > >> If you try that and evaluate all the cells in order, then you'll see > >> that changing a and b > >> causes all the other dependent cells to update. You can add > >> non-dependent cells and > >> they won't update. Obviously the above is a bit cumbersome, but could > >> be made smoother > >> if it gets at what you're after. > > >> William > > > After all, I'd be glad to see if any interest is shown in this > > direction, since there is a reasonable amount of work around the > > notebook now. Otherwise, thank you for the discussion :) > > > Maurizio > > -- > William Stein > Associate Professor of Mathematics > University of Washingtonhttp://wstein.org --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
