On Sat, Mar 28, 2009 at 5:28 AM, Jason Grout <jason-s...@creativetrax.com> wrote: > Aha, the one custom infix operator that I know of in Sage. > > In the backslash operator and in the article posted, the rmul only > stored the argument and the __mul__ only performed the operation. Are > you always guaranteed that __rmul__ will be called right before __mul__ > for the same invocation of the operation?
Hmm... probably not. Consider A *emul* (B *emul* C) Since multiplication is left-associative, this is: (A*emul)*((B*emul)*C) This is probably (I don't know if Python guarantees left-to-right evaluation, but I'm guessing it does) evaluated in this order: t1 = A*emul t2 = B*emul t3 = t2*C t4 = t1*t3 So for safe general-purpose use, A*emul needs to return a new object. Carl --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send 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 -~----------~----~----~----~------~----~------~--~---
