Hi! On Sep 2, 7:40 am, Jason Grout <jason-s...@creativetrax.com> wrote: > Wow, that seems totally ambiguous. Is 5!!! equal to (5!!)! or (5!)!! or > ((5!)!)! The notation is pretty bad in this case. [...]
Yes, and this is why the very common notation "5!" is bad syntax that should be avoided in a CAS, IMHO. Of course, one could say that "5!" should mean "factorial of 5" unless the following character is "=" as in "5!=3" or "!" as in "5!!". But I wouldn't paint a bike shed in that way. Just imagine how much fun it is to find a bug like "5! !" (which probably is factorial(factorial (5))) versus "5!!" (which probably is double_factorial(5)). If one starts like that, why not continue with [5] (quantum deformed integers) and [5]! (quantum factorial)? Or another very common notation: Should Sage really support "d^2f(x,y)/ (dx*dy)" to construct partial derivatives? I think that a CAS without a strong programming language is nothing but a simple pocket calculator. Therefore, if a mathematical notation interferes too much with the requirements of the underlying programming language, then the mathematical notation should be dropped. Compare this with the example given by Kwankyu: R<x>=ZZ[] resembles a chain of inequalities, sage: 5<6>=3 True and R[x] is not compatible with Python's syntax (if R is to be defined). Therefore, I think it is a very reasonable compromise to have the additional dot in R.<x> Cheers Simon --~--~---------~--~----~------------~-------~--~----~ 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 URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
