On Sat, 28 Oct 2006 12:28:04 -0500, Joel B. Mohler <[EMAIL PROTECTED]> wrote:
> > On Sat, Oct 28, 2006 at 02:18:56AM -0500, William Stein wrote: >> >> Hello, >> >> I implemented the idea that Bill Hart suggested this morning. In the >> next version of SAGE the following will work: > > What does the following do? > sage: x=5 > sage: QQ['x'] > sage: print x > > IMO, it should give an exception indicating that x is already > defined at the QQ['x'] line since a python programmer would not expect a > new variable to be defined by that line. It overwrites x. > The actual results of > sage: QQ['x'] > sage: GF(9)['x'] > also seem a bit uncomfortable. I guess (in keeping with my opinion > above) that the second line should throw the exception. Somehow this > seems like an annoying restriction, but I'm not sure. Doing that might make the system unusable. If you did sage: MPolynomialRing(ZZ,'x',5) Polynomial Ring in x0, x1, x2, x3, x4 over Integer Ring sage: x2^2 + x3^3 x3^3 + x2^2 sage: MPolynomialRing(GF(7),'x',5) Polynomial Ring in x0, x1, x2, x3, x4 over Finite Field of size 7 sage: x2^2 + x3^3 x3^3 + x2^2 With your model you would have to explicitly go through and delete each of x0 x1 x2 etc, just because you decided to change rings. ---- I just spent a week with 50 serious algebraic geometry computation people, and having sage: x = 5 sage: QQ['x'] leave x equal to 5 really confuses them. Anyway, a Python program would not understand " QQ['x'] " since thats the notation for list indexing and in Python it would return an element of QQ, I suppose. William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com 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/ -~----------~----~----~----~------~----~------~--~---
