Re: Is V? what we need ?

> Here comes the parallel with Integer, the way we use Integer currently is, i > believe, the way we should use V*. It's fine to use V* as a type argument, > it's fine to use it in a field if you want the reference semantics or a null > value. It's not fine to use Integer as parameter of a

Re: Is V? what we need ?

- Mail original - > De: "John Rose" > À: "Remi Forax" > Cc: "Brian Goetz" , "valhalla-spec-experts" > > Envoyé: Jeudi 2 Mai 2019 04:17:54 > Objet: Re: Is V? what we need ? > It looks like we're getting somewhere; t

Re: Is V? what we need ?

On 01/05/2019 20:34, Brian Goetz wrote: ne big difference between whether we convert V to V? via subsumption or via a boxing conversion is how overload selection is done.  But, if we have methods m(Object) and m(V?), and it is invoked with a v, in the subtyping case, we'll select m(Object),

Re: Is V? what we need ?

It looks like we're getting somewhere; thanks for the detailed response. I have one targeted reply: On May 1, 2019, at 4:38 PM, fo...@univ-mlv.fr wrote: > > So let's call it V*. I want also make clear that there is no proposal to not > have a V*, we need it, and it's the L-version of an inline

Re: Is V? what we need ?

- Mail original - > De: "John Rose" > À: "Brian Goetz" > Cc: "Remi Forax" , "valhalla-spec-experts" > > Envoyé: Jeudi 2 Mai 2019 00:55:19 > Objet: Re: Is V? what we need ? > On May 1, 2019, at 7:50 AM, Brian Goetz wrote: &

Re: Is V? what we need ?

I buy your argument, Brian, for shedding boxes from the center of the user model for V and V?. Given that V and V? have different contracts (per my previous note), so that they can have different physical representations in the JVM, it turns out that this statement: V is a subtype of V? (for

Re: Is V? what we need ?

On May 1, 2019, at 7:50 AM, Brian Goetz wrote: > >> I fully agree, it's like getting ride of Integer, it's a fantasy, but not >> having a lot of API taking a N? as parameter type make that fantasy actually >> possible for the libraries you care. > > We can’t get rid of Integer, but maybe we

Re: Is V? what we need ?

On May 1, 2019, at 6:28 AM, Brian Goetz wrote: > > Also, we’re conflating two separate questions here. > > 1. What does V? mean. In the proposed world, it is the union type of V and > Null, nothing more (alternately: V adjoined with null.). > > 2. What is the relationship between V and

Re: Is V? what we need ?

However, I think my more general point remains - the fact that the VM has the flexibility to treat V and V? as, fundamentally, the same thing shouldn't necessarily drive the conclusion that, _at the language level_ there should be a subtyping relationship between V and V?. From a

Re: Is V? what we need ?

between the two, which means it would work on assignment context and method calls (albeit with lower priority w.r.t true subtypes, which is what we want anyway). Maurizio On 01/05/2019 13:57, Remi Forax wrote: Brian ask me to make it its own thread. so is V? what we need, because i believe we have

Re: Is V? what we need ?

- Mail original - > De: "Brian Goetz" > À: "Doug Lea" > Cc: "valhalla-spec-experts" > Envoyé: Mercredi 1 Mai 2019 16:39:59 > Objet: Re: Is V? what we need ? > This is the point I’ve been failing to get across to Remi as well. Suppose

Re: Is V? what we need ?

ec-experts" > Envoyé: Mercredi 1 Mai 2019 16:32:18 > Objet: Re: Is V? what we need ? > On 5/1/19 10:12 AM, Brian Goetz wrote: >> >> You’re assuming the utility of V? after reification is zero, but >> that’s not the case. For example, suppose ArrayList is

Re: Is V? what we need ?

> > I fully agree, it's like getting ride of Integer, it's a fantasy, but not > having a lot of API taking a N? as parameter type make that fantasy actually > possible for the libraries you care. We can’t get rid of Integer, but maybe we can make it 10x less important. That would be winning.

Re: Is V? what we need ?

- Mail original - > De: "Brian Goetz" > À: "Remi Forax" > Cc: "Maurizio Cimadamore" , > "valhalla-spec-experts" > > Envoyé: Mercredi 1 Mai 2019 16:12:05 > Objet: Re: Is V? what we need ? >>> Boxes are not a good

Re: Is V? what we need ?

This is the point I’ve been failing to get across to Remi as well. Suppose you have a big value, and you want a sparse ArrayList of that value? You need a way to say “Arraylist of BigValue, but not flattened.” And that’s a use-site concern. ArrayList gives you that. Which is to say: the

Re: Is V? what we need ?

On 5/1/19 10:12 AM, Brian Goetz wrote: > > You’re assuming the utility of V? after reification is zero, but > that’s not the case. For example, suppose ArrayList is reified. Then > the user gets the choice of erasure or reification by selecting > ArrayList or ArrayList. Erasure has a bad rap,

Re: Is V? what we need ?

> De: "Brian Goetz" > À: "Remi Forax" > Cc: "valhalla-spec-experts" > Envoyé: Mercredi 1 Mai 2019 15:24:42 > Objet: Re: Is V? what we need ? >> a box is a necessary evil, everybody want to write an ArrayList but we >> are >>

Re: Is V? what we need ?

>> Boxes are not a good thing; they were a necessarily evil that arises from the >> fact that primitives are not objects. But they create many problems of their >> own. I don’t see how “more boxes” is the answer here. > > More boxes is a temporary answer until we have fully reified generics

Re: Is V? what we need ?

- Mail original - > De: "Brian Goetz" > À: "Maurizio Cimadamore" > Cc: "Remi Forax" , "valhalla-spec-experts" > > Envoyé: Mercredi 1 Mai 2019 15:13:06 > Objet: Re: Is V? what we need ? > But, this is Q-world thinking. In

Re: Is V? what we need ?

Also, we’re conflating two separate questions here. 1. What does V? mean. In the proposed world, it is the union type of V and Null, nothing more (alternately: V adjoined with null.). 2. What is the relationship between V and V? — is it sub typing, or conversion? I think Remi is more

Re: Is V? what we need ?

> > a box is a necessary evil, everybody want to write an ArrayList but we > are not there yet, so we provide just the right abstraction to deal with > value type in generics, not more. I think this is where we part ways. In Java 1.0, with respect to primitives, a box was a necessary evil,

Re: Is V? what we need ?

- Mail original - > De: "Brian Goetz" > À: "Remi Forax" > Cc: "valhalla-spec-experts" > Envoyé: Mercredi 1 Mai 2019 15:03:42 > Objet: Re: Is V? what we need ? >> we need V? >> - to represent the L variation of a Q

Re: Is V? what we need ?

ity w.r.t true subtypes, which is what we want anyway). > > Maurizio > > On 01/05/2019 13:57, Remi Forax wrote: >> Brian ask me to make it its own thread. >> so is V? what we need, because i believe we have been a little over our own >> head on this and loose the sigh

Re: Is V? what we need ?

(albeit with lower priority w.r.t  true subtypes, which is what we want anyway). Maurizio On 01/05/2019 13:57, Remi Forax wrote: Brian ask me to make it its own thread. so is V? what we need, because i believe we have been a little over our own head on this and loose the sight of what we need

Re: Is V? what we need ?

> we need V? > - to represent the L variation of a Q type. > - to interact with generics that are not reified. These are the proximate causes, but I think this undersells it. > V? does that but does far more, V? is a super type of V which is dangerous, > because people will use it as

Is V? what we need ?

Brian ask me to make it its own thread. so is V? what we need, because i believe we have been a little over our own head on this and loose the sight of what we need for V?. we need V? - to represent the L variation of a Q type. - to interact with generics that are not reified. V? does