> De: "Gavin Bierman" <gavin.bier...@oracle.com> > À: "Remi Forax" <fo...@univ-mlv.fr> > Cc: "jan lahoda" <jan.lah...@oracle.com>, "amber-spec-experts" > <amber-spec-experts@openjdk.java.net> > Envoyé: Mardi 18 Février 2020 16:16:40 > Objet: Re: Pattern Matching for instanceof (Preview 2)
>> On 18 Feb 2020, at 15:04, [ mailto:fo...@univ-mlv.fr | fo...@univ-mlv.fr ] >> wrote: >> Hi Gavin, >> ----- Mail original ----- >>> De: "Gavin Bierman" < [ mailto:gavin.bier...@oracle.com | >>> gavin.bier...@oracle.com ] > >>> À: "Remi Forax" < [ mailto:fo...@univ-mlv.fr | fo...@univ-mlv.fr ] > >>> Cc: "jan lahoda" < [ mailto:jan.lah...@oracle.com | jan.lah...@oracle.com ] >>> >, >>> "amber-spec-experts" < [ mailto:amber-spec-experts@openjdk.java.net | >>> amber-spec-experts@openjdk.java.net ] > >>> Envoyé: Mardi 18 Février 2020 15:32:12 >>> Objet: Re: Pattern Matching for instanceof (Preview 2) >>> [Just circling back to this, as I added a note about the grammar to the JEP >>> page…] >>>> On 6 Feb 2020, at 20:38, Remi Forax < [ mailto:fo...@univ-mlv.fr | >>>> fo...@univ-mlv.fr ] > wrote: >>>> [moved to amber-spec] >>>> ----- Mail original ----- >>>>> De: "jan lahoda" < [ mailto:jan.lah...@oracle.com | jan.lah...@oracle.com >>>>> ] > >>>>> À: "amber-dev" < [ mailto:amber-...@openjdk.java.net | >>>>> amber-...@openjdk.java.net ] > >>>>> Envoyé: Jeudi 6 Février 2020 21:18:52 >>>>> Objet: Pattern Matching for instanceof (Preview 2) >>>>> Hi, >>>>> Thanks to Gavin, Brian and Alex, there is a new draft JEP for Pattern >>>>> Matching for instanceof (Preview 2): >>>>> [ https://bugs.openjdk.java.net/browse/JDK-8235186 | >>>>> https://bugs.openjdk.java.net/browse/JDK-8235186 ] >>>>> Any feedback on the JEP is more than welcome! >>>>> Thanks, >>>>> Jan >>>> so the difference with the previous preview is that deconstruction is >>>> added. >>> That is correct. >>>> I see two questions: >>>> - the grammar allows to mix var and non-var for a given reference type, i >>>> think >>>> that should only permitted if the non var is a deconstruction itself ? >>> I don’t know what you mean here. There are two patterns, a type test >>> pattern and >>> a deconstruction pattern. In v2 we propose to support deconstruction >>> patterns >>> over record types *only*. A deconstruction pattern looks like this: >>> Point(var >>> a, var b), i.e. all the components are either (recursively) deconstruction >>> patterns, or `var` <identifier>, i.e. with no type needed. I added a note to >>> the JEP page pointing out that this is a starting point, and eventually we >>> will >>> support other patterns in the argument position, specifically <type> >>> <identifier>; hopefully in this release. >> Currently we don't support mixing var and non var in lambda parameters. >> So my question is: does this pattern Point(var x, int y) that mix a 'var' >> and an >> explicit type allowed or not ? > Aha. So, we’re not at that stage yet - this isn’t allowed by the spec as it > stands. This - and many other issues - is why I’m starting small… > Do you have a preference? I don't think it's a matter of preference, we want to support things like Rectangle(var p1, Point(var x, var y)) For the type pattern Rectangle(...), there is a mix between var and non var, no ? > Gavin Rémi
