On 19-Sep-07, at 8:09 PM, William Stein wrote:
> > On 9/19/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: >> I am rather fond of the '..' operator, though I can see why people >> wouldn't want to add it as an official part of sage. This got me to > > I think the decision about whether or not to include something like > this is definitely not decided yet. I personally also really like > the > [a..b] notation, since I really enjoyed using it in Magma, and I > think perhaps the complaints about 0 or 1-based are misplaced, > because with the [a..b] notation one is being completely explicit > about the lower endpoint. Also, the closed brackets very very > very strongly suggest "include the endpoint", like the do in standard > mathematical notation. Also, I was not convinced that preparsing > [a..b] is not possible in general (though Nick was worried about > this).\ It's not that it's not possible, it's that soon you have to parse arbitrary python code, or accept that you can break the preprocessor. > I am going to wait a while to see what brews up, even though > the majority vote was against [a..b]. > > At a minimum I would like to implement that for the preparser (or > have somebody else do so), and see what it feels like to use in > practice > in Sage. I think tomorrow I will do this, and perhaps refactor the preparser slightly while I am there. It seems like we should be able to use open and half open intervals, so not only [1..2] and (0..3) are valid but also are [0..2) and (0..2] are. In fact, I will try to specify an encoding to range that allows for something like [0, 2, .. 8) which should be [0, 2, 4, 6] by my calculation. As for iterators versus lists, I favour distinct notations for distinct ideas. Perhaps <[ and )>? I don't know. Nick --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
