How about a compromise: if the user uses the command-line-only shortcut forms like R.<x,y>=... or R=QQ[x,y] which go through preparsing, then it is checked that the names provided are distinct (from each other only). But in library code this is not checked, or at least no more than at present where this is useful:
sage: R1 = PolynomialRing(ZZ,'x') sage: R2 = PolynomialRing(ZZ,2,'xy') sage: R1.gens() (x,) sage: R2.gens() (x, y) sage: x = R1.gen(0) sage: x in R2 True On 29 September 2014 17:34, 'luisfe' via sage-devel <sage-devel@googlegroups.com> wrote: > In fact, I think that this feature is explicitely allowed and that, as long > as you stay within the sage library, code should not break for having a ring > with repeated variables. > > However, I agree that it is weird. > > Funny example: > > sage: K=QQ['x,y,y,x'] > sage: sum(K.gens()) > x + y + y + x > sage: _(x=1,y=2) > x + y + 3 > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
