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> For example, while Valhalla has taken several years so far, OpenJDK team has experimental builds that you can go and play around with value types in Java. A

> For example, while Valhalla has taken several years so far, OpenJDK team has experimental builds that you can go and play around with value types in Java. Actually Valhalla is pretty interesting to think about. For what I'm currently working on, the inability to have a list of points without individually heap-allocating each one makes a language much more of a non-starter than the lack of user-defined parameterized types does. Even back when Java was invented, there was plenty of prior art (going back decades) about efficiently representing a list of points in memory. Probably most of its predecessors could do it. Yet Java has lacked this basic ability for 25 years. I even expect that when they eventually implement it it will work similarly to other popular languages, compared to Go which seems to be drawing on more recent developments (like concepts etc) for its generics design. Despite this, I don't accuse the Java team of political machinations every time the topic comes up. Mainly because I don't believe that to be the case. Maybe they've prioritized a critical feature for me lower than I would like, but it seems like a substantial amount of work to implement because (like generics) it interacts with other language features in a complex way and (like generics) once they ship a design they will be stuck keeping backwards compatibility with it basically forever, so they only have one chance to get it right.

pjmlp 6y ago
The difference being that Java teams deliver language improvements and go on the stand acknowledging where to improve and setting roadmaps, Go not so much. Even stuff like error handling improvements and type alias were almost shot down.
- throwaway34241 6y ago
  > The difference being that Java teams deliver language improvements Sure, I think it's fair to say they've focused a lot more on implementation and library changes and not language changes up until recently. Things like rewriting the compiler from C, improving code generation / escape analysis / GC, more platform / architecture support, improving the standard library, getting a reasonable package manager, etc. So it seems a little premature to read some secret anti-generics stance into it (and it not just being a matter of priorities) since there were all these other areas that they were also way behind Java in. After package management was in generics started showing signs of life again, so it all seems reasonably consistent with the Go team just wanting to clear other stuff off their plate first before tackling it. Hopefully we see it in a similar timeframe to major Java/C++ features now that it's being worked on more. If there's any silver lining the actual proposals seem pretty ambitious, seems like they want to enable a lot more than just new type safe collections if they add the feature.

pjmlp 6y ago

The difference being that Java teams deliver language improvements and go on the stand acknowledging where to improve and setting roadmaps, Go not so much. Even stuff like error handling improvements and type alias were almost shot down.

throwaway34241 6y ago
> The difference being that Java teams deliver language improvements Sure, I think it's fair to say they've focused a lot more on implementation and library changes and not language changes up until recently. Things like rewriting the compiler from C, improving code generation / escape analysis / GC, more platform / architecture support, improving the standard library, getting a reasonable package manager, etc. So it seems a little premature to read some secret anti-generics stance into it (and it not just being a matter of priorities) since there were all these other areas that they were also way behind Java in. After package management was in generics started showing signs of life again, so it all seems reasonably consistent with the Go team just wanting to clear other stuff off their plate first before tackling it. Hopefully we see it in a similar timeframe to major Java/C++ features now that it's being worked on more. If there's any silver lining the actual proposals seem pretty ambitious, seems like they want to enable a lot more than just new type safe collections if they add the feature.