On 30-May-2011, at 11:05 PM, julius wrote: > > On 30 May 2011, at 15:52, Roland King <r...@rols.org> wrote >> >> On 30-May-2011, at 9:18 PM, julius wrote: >> >>> >>>> They used the datatype which maps onto the thing they are describing, >>>> array elements are non-negative integers, so they used NSUInteger. >>> So are you saying that the designers made this decision solely because of a >>> particular interpretation of dogma? >> >> No. I am saying that semantically the 'size' of an array is a non-negative >> integer and thus the correct way to represent it is with a data type which >> represents non-negative integers. > > If that were all there was to it then I might agree but I don't think it is. > I think issues of program language complexity and the propensity of language > constructs to induce coding errors are more important. > > Julius >
Whist seeing your side, I respectfully disagree. I think data types should as closely as possible align with the data they actually represent. Perhaps the best solution would be an object data type for size of an array which had syntax which stopped anyone misusing it, methods for iteration, for comparison etc. which left no way to make an error (I think that's called C++ :) ). I'm personally very happy with unsigned integer for size of/index into array and when I see 'unsigned' on a type I'm reminded what comparisons are valid on the zero side; I will admit to having blown myself up on more than one occasion overflowing a type on the high side, I've rarely messed up subtracting unsigned types without considering whether the subtraction is valid, but I'm sure there was a time years ago I learned that lesson and probably the hard way. I still think that if you do reasonable checks on array sizes before you use them, most comparisons are valid for sizes without issue and those checks always seem to me to be part of the logic you should be writing anyway to differentiate cases. I like NSUInteger because it reminds me what type of data I'm really dealing with. If Cocoa used NSInteger I'm sure I'd have gotten used to that as well, and I'm sure I'd have found a few cases in which I'd wondered why they didn't do it the unsigned way. > > > http://juliuspaintings.co.uk > > > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
