Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

I have written a JVM in Rust

andreabergia.com

Post reply on HN
Print view View original

21–30 of 185 posts

Re: I have written a JVM in Rust

#21

Post by cmrdporcupine »

dimgl wrote: post #17
xmcqdpt2 wrote: post #10

Earlier quoted context omitted.

Also https://github.com/lihaoyi/Metascala for a JVM implemented in Scala running on the JVM.

Seems… redundant, no?

"The goal of Metascala is to create a platform to experiment with the JVM: a 3000 line JVM written in Scala is probably much more approachable than the 1,000,000 lines of C/C++ "

Seems like a reasonable goal.

Re: I have written a JVM in Rust

#22

Post by cmrdporcupine »

maverwa wrote: post #3

Great project, congrats! Mad respect. Started working on something very similar a few years back and gave up pretty soon for some stupid reason. Maybe I should try again, am getting better at getting stuff done.

You should. I've been doing this kind of stuff on the side for 25+ years, and nothing ever gets "done." But the educational value is much higher than you think. And the skills learned can eventually propagate out into interesting paid work.

I think of them as retirement projects before I retire. When I actually retire I'll maybe finish them.

(That said, I have in the past tried taking jobs that were adjacent to my "research" interests, and found the joy of building these things from scratch is much better than fiddling with the levers on the side of someone else's thing they built from scratch years ago. I like working on and improving production systems, but if they intersect too closely to my personal interests, it can be demoralizing.)

Re: I have written a JVM in Rust

#23

Post by maverwa »

3cats-in-a-coat wrote: post #18
maverwa wrote: post #14

Earlier quoted context omitted.

I think op meant "String literals". For those the spec seems to require interning: > Moreover, a string literal always refers to the same instance of class String. This is because string literals - or, more generally, strings that are the values of constant expressions (§15.28) - are "interned" so as to share unique instances, using the method String.intern. And later: > Literal strings within different classes in di…

Thanks, makes sense yes. Still if the JVM look up in all cases defers to value after ref mismatch, it should work identically, no? Even if interning is mandatory as per spec, I'm not sure how it'd change the outcome of evaluation.

yeah, I'd assume as much. If it indeed falls back to a by-value comparison it would be slower, but should work.

Re: I have written a JVM in Rust

#25

Post by robertlagrant »

3cats-in-a-coat wrote: post #18
maverwa wrote: post #14

Earlier quoted context omitted.

I think op meant "String literals". For those the spec seems to require interning: > Moreover, a string literal always refers to the same instance of class String. This is because string literals - or, more generally, strings that are the values of constant expressions (§15.28) - are "interned" so as to share unique instances, using the method String.intern. And later: > Literal strings within different classes in di…

Thanks, makes sense yes. Still if the JVM look up in all cases defers to value after ref mismatch, it should work identically, no? Even if interning is mandatory as per spec, I'm not sure how it'd change the outcome of evaluation.

Yes - that is a performance optimisation. I don't think comparing everything by value makes or breaks the implementation.

Re: I have written a JVM in Rust

#28

Post by dgb23 »

capableweb wrote: post #20
hajmo97 wrote: post #16

How often will this post be reposted on HN ? Recent posts: https://news.ycombinator.com/item?id=36735344 - 6 days ago https://news.ycombinator.com/item?id=36717967 - 7 days ago https://news.ycombinator.com/item?id=36710803 - 7 days ago (OP) Btw. nice project!

Doesn't really count as a repost if none of the previous submissions didn't get any traction.

I agree, plenty of technically interesting projects don’t get discussion on hn. There’s always a bit of luck and context involved.

Re: I have written a JVM in Rust

#29

Post by thfuran »

3cats-in-a-coat wrote: post #18
maverwa wrote: post #14

Earlier quoted context omitted.

I think op meant "String literals". For those the spec seems to require interning: > Moreover, a string literal always refers to the same instance of class String. This is because string literals - or, more generally, strings that are the values of constant expressions (§15.28) - are "interned" so as to share unique instances, using the method String.intern. And later: > Literal strings within different classes in di…

Thanks, makes sense yes. Still if the JVM look up in all cases defers to value after ref mismatch, it should work identically, no? Even if interning is mandatory as per spec, I'm not sure how it'd change the outcome of evaluation.

It affects the result of ==, which is only a reference comparison.
Post reply on HN