On Tue, 12 Mar 2019 at 21:56, Marcus Denker <marcus.den...@inria.fr> wrote: > > Hi, > > Yes, I do not like it… I think it is there so that you can just make a > variable subclass and at: / at:put: will work without > having to re-implement them…
So we should consider... * how often are variable subclasses created ? by novices or experts ? * how much work is it to reimplement those methods ? how difficult to know what needs to be done ? * what is the balance cheers -ben > > Marcus > > On 12 Mar 2019, at 04:55, Richard O'Keefe <rao...@gmail.com> wrote: > > I understand #basicAt:[put:] being in Object, but I never understood > #at:[put:] being there. > GNU Smalltalk: > st> nil at: 1 > Object: nil error: Invalid value nil: object not indexable > In my Smalltalk, you get a DNU. > In Squeak you get a debugger window with title > Error: instances of UndefinedObject are not indexable > The same for Boolean, Character, and Integer, > except Squeak where (20 factorial at: 1) answers 0 (oh dear oh dear oh dear). > In VW you get a "Subscript out of bounds" error, which is disappointing, > as do true and $a, but a LargePositiveinteger gets #shouldNotImplement. > > > On Tue, 12 Mar 2019 at 15:28, Tim Mackinnon <tim@testit.works> wrote: >> >> If you forget to initialise a variable which you thought was a Dictionary - >> you get a confusing error message: "Error: only integers should be used as >> indices” if you try an at:put: >> >> This is a consequence of having at:put: defined on Object (which is a bit >> nasty) >> >> Should UndefinedObject at least override this and signal something a bit >> more obvious? This is a common and easily done thing and we don't support it >> very well. >> >> I just did it in some code, and was scratching my head initially until I >> read the stack properly and realised it was something much simpler than I >> thought I had done. >> >> Any thoughts on this? > >
