> Currently the rule is that if you can do arithmetic between two > elements, you can compare them. Membership code is something entirely > different.
Very mathematical... Is the imaginary i bigger or smaller than 1? [snip] > Membership is much more lenient than coercion, for example, I would > be more worried if the following returned False > sage: 4/2 in ZZ > True But why? ZZ(4)/ZZ(2) cannot be executed in ZZ, because ZZ is a ring and by default has no /. ZZ(4)/ZZ(2) just stands for "the x such that 2*x == 4", i.e. is the result of a solving process which might fail. If ZZ(4)/ZZ(2) gives by default a rational number than coercion back to ZZ involves at least testing whether the (canonical) denominator is equal to 1. That costs time. Is it somehow possible to distinguish between library code and interactive code? In library code, I would prefer to have coercions *not* automatically applied. For the interactive mode autocoercion makes sense, since anything else would bother users too much. [snip] > I would like to avoid having a whole hierarchy of coercions, some of > which are used in some cases, others in other cases. People have > enough trouble understanding the system as it is. Well, that, of course, must be taken into account. But as Nicolas said, applying projections by default (I think) is not a good idea. Ralf --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
