Puzzlers aside, can we get a definitive answer on why this is this way? I want to understand the semantics by the compiler that made this possible, so that I can understand why it is being considered legal by the compiler. Is what Deepak says is true?
On Fri, Sep 5, 2025 at 12:46 PM Remi Forax <fo...@univ-mlv.fr> wrote: > ----- Original Message ----- > > From: "Brian Goetz" <brian.go...@oracle.com> > > To: "Simon Ritter" <srit...@azul.com>, "amber-dev" < > amber-dev@openjdk.org> > > Sent: Friday, September 5, 2025 4:30:06 PM > > Subject: Re: Question on Primitive Types in Patterns > > >> > >> I've been giving a presentation on Patterns in the Java language and > >> including some puzzles. The recent inclusion of Primitive Types in > >> Patterns has provided some interesting material. I currently have one > >> puzzle that I can't quite explain; hopefully someone on the mailing > >> list can provide clarification. > > > > On a pedagogical note, I'd like to make a case for "Java Puzzlers Talks > > Considered Harmful." They can be fun to write (which is why we get so > > many of them), but I have found that the vast majority of time, a good > > chunk of the audience comes away with notions that are closer to "XYZ is > > broken", "XYZ is just all ad-hoc complexity", or "XYZ has no organizing > > design principle" -- even though this is rarely the intent of the > > presenter (often the opposite, in fact.) > > > > When Josh and Neal started with Puzzlers, they could at least come from > > the position of "these were some arguably-mistakes that *we* made". Not > > only did this give them credibility that almost no other "Java Puzzlers" > > presenter could have, but it pushed them to dig deeper to present > > language design tradeoffs _from the perspective of language designers_. > > > > I cannot count the number of times where someone has seen a "puzzler" > > presentation or blog, and learned the exact opposite lesson than it was > > trying to teach. This is an extraordinarily difficult format for > > teaching. Worse, the nature of a "Puzzlers" talk requires having a > > bunch of them, and -- even when Josh and Neal did it -- there were > > always a few that didn't live up to the standards; the format often > > overtakes the message. It is just a truly punishing format, one that > > requires world-class pedagogy and impeccable preparation to avoid the > > all-too-common outcome where many in the audience learn the wrong lesson > > (often reinforcing their preconceived but ill-examined assumptions about > > "X is bad.") > > This is a preview feature, so for me finding corner cases is fair game. > It help us to understand the tradeoffs of this feature. > > There are always puzzlers, for every features, but there are two > categories of puzzlers: > - those that enlighten you (like this is why Foo behave different as a top > level pattern or as an inner pattern), > as you said, it's quite hard to convey that in a presentation. > - those that just show the designers being too clever (lets make ?: boxing > rules different) > or the feature being consistent only with itself and not with the rest > of the world (the X cross Y problem). > > regards, > Rémi >
