On Wed, Jan 29, 2020 at 13:04 ToddAndMargo via perl6-users < perl6-us...@perl.org> wrote:
> On 2020-01-29 09:19, Trey Harris wrote: > > > > The first line of https://docs.raku.org/type/UInt is: > > > The `|Int`| is defined as a subset of `|Int|:` > > > > How does that not “reflect that UInt is not a unique [type, I assume you > > meant], but a subset of Int”? > > You are correct. Mumble, mumble. > > > > > > 2) that uint is not a native type, but a subset of int. > > > > > > But `uint` is not a subset of `int`; they’re both native types so can’t > > be subtypes as the constraints would have to hook to the metamodel, > > which uint and int lack because they’re unboxed. (A “sticker on the > > “box” is where you write the constraints, if you want to think of it > > that way.) > > So long as it is treated as a subset of int, it is a subset. “treated as a subset”? I don’t know what you mean: ```console > int.does(uint) False > uint.does(int) False > int.isa(uint) False > uint.isa(int) False > UInt.does(Int) True > Int.does(UInt) True > UInt.isa(Int) True > Int.isa(UInt) False ``` If I write: ``` class A { has Int $.value } class B { has Int $.value where * ≥ 0; } ``` B is not a subset of A. That is the relationship of uint and int—two distinct types whose values happen to overlap in a way that describes a subset. Perl isn’t Prolog; a logical relationship between two types is not a first-class entity of the language. > > I know, I am slicing the baloney thin here, but uint is > not a static C variable. It can change into an int with > the position of the moon. I’m STILL waiting for you to show me ONE example of a `uint` turning into `int`. Not `Int`, via auto-boxing, `int`, via who-knows-what. Either do that, or stop making the assertion it does that; if you don’t show a reproducible example, I am going to conclude you are lying if you persist.
