On Wed, May 4, 2016 at 10:07 PM, Johan S. R. Nielsen <santaph...@gmail.com> wrote: > Michael Orlitzky writes: >> I have a matrix m... how come, >> >> * m.rank gives me bullshit >> * m.rank() works >> * m.T() crashes >> * m.T works? > > This is in my mind the most compelling reason to phase out properties in > Sage. I think Erik makes many good points, but ultimately I think > consistency is more important. The problems with ? and tab-completion > seem manageable, so I leave that aside. > > In many ways, programming math is a software designers worst nightmare, > where designing the good API that is logical and works in all cases > quickly becomes daunting. Michael's example above is nice: the rank of a > matrix is an invariant, so it should just be a read-only property, just > like all the my-first-@property-tutorials tells us, right? But by that > logic, tons and tons of zero-argument methods should be read-only > properties in Sage. And if someone later on implements a clever > algorithm2 for computing the rank of certain types of matrices, and > would like to toggle that by an optional argument, @property is suddenly > a problem. And so where would you draw the line?
I think I agree with you here--I think ideally something like rank should be a property, but there are good exceptions where it shouldn't be, and so for the sake of consistency it shouldn't be in general. I think matrix.T is a special case that should be viewed as syntactic magic (and could be handled better with a better implementation of "?"). I was mostly just objecting to Michael's earlier comment that @property is not useful *in general*, and that's demonstrably not true. But I've come to understand and agree with the overall sentiment here that it should be employed *carefully* in Sage. -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
