> On Aug 1, 2016, at 8:28 PM, Rick Mann via swift-users <swift-users@swift.org> > wrote: > > It sure seems natural. > > Is there some reason the language can't allow a sub-struct to add member > variables, such that the whole is treated like a contiguous set of members? > > In my case, I have a rect-like value type, but I'd rather it inherit from > CGRect, rather than contain a CGRect. That makes it much more natural to use. > > Is allowing that just too complicated, or does it create type safety issues? > > -- > Rick Mann > rm...@latencyzero.com
Inheritance isn't really compatible with value types at least if they're allocated on a stack (known as "stack-dynamic) and take a fixed amount of space (think about what would happen if you assigned it to a subclass that had additional data - no room to store the additional data). References are typically stored on a heap with a pointer to the object stored on a stack (pointers takes the same amount of memory no matter what type they point to). If you don't need extra data (additional instance variables), you can add new methods to CGRect using extensions. HTH, Dave Reed _______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
