On Monday, March 26, 2012 9:32:45 AM UTC-7, Keshav Kini wrote: > > Simon King writes: > > sage: is_Integer(int(5)) > > False > > sage: is_Integer(5/1) > > False > > sage: int(5) in ZZ > > True > > sage: 5/1 in ZZ > > True > > Huh. It seems like this is the opposite of what you'd expect, doesn't > it? "object in object" seems to be a query of whether a certain thing is > in a certain data structure, i.e. seems like it should be > literal-type-aware, whereas "semantic_function_name(object)" seems more > likely to have a mathematical, abstract meaning. > The functions like "is_Integer" are deprecated. If you compare the alternative
isinstance(5/1, Integer) with 5/1 in ZZ I definitely want the first to return False, and I'm also happy if the second returns True. It makes more sense to me for the second to have a mathematical, abstract, meaning, because it is more natural and more likely for a user to execute. I think we should view our users as mathematicians first, so I like things as they are. (Another way to say it is that "x in Y" should take coercions and related operations into account, as "5/1 in ZZ" does. If there is a canonical one-to-one map from S to T, then every element of S should be "in" T. Every element of a group should be "in" the corresponding group algebra, etc.) -- John -- 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 URL: http://www.sagemath.org
