Introducing the OCaml Local Mode | OCaml Unboxed

[@SkinnyGeek_1010]

What an excellent video! I fully expected to watch a dry whitepaper type of video but this was easy to absorb :)

[@mathiassven]

Glad to see you back on YT! I might pick up OCaml just so I can follow along, your videos are always incredibly insightful on whatever topic you speak on

[@jslee0909]

So it's like Rust lifecycles without that manual memory management. Nice

[@anarchymatt]

It's the guy from the Tweag videos 😃

[@RichardEisenberg-JS]

Happy to be back on KZbin. 😁

[@vedthiru575]

FYI, there's a typo in the link to the compiler (it takes me to the branch "with-extepensions" instead of "with-extensions").

[@donbasti]

Eisenberg - "IO monad is nothing but passing in the World as a parameter to your function" (or smth like this)

[@drew-et1mm]

its a lifetime annotation!

[@RichardEisenberg-JS]

Indeed! Well, it's a little different from Rust's interpretations of lifetime (ours are simpler; Rust's are more expressive). But I didn't want to start by assuming knowledge of Rust.

[@user-uf4lf2bp8t]

​@@RichardEisenberg-JSI think simpler is better for something that can become as mind-numbing to take care of manually as lifetimes. In rust, they tend to blow up, pushing you to just clone everything everywhere

[@hsyl20]

It would be nice to have this in Haskell too! We could assert that a param isn't stored in a thunk (think `DynFlags` in GHC itself). How difficult would that be to implement?

[@RichardEisenberg-JS]

I think thunks should be fine; it's just that the thunk itself would have to be local in order to capture local data. It would be a pretty major lift, though -- getting this working in OCaml wasn't easy. (I don't take credit, as most of it was implemented before I started at Jane Street.)

[@dmmulroy]

This is cool, great intro to the topic!

[@SlickMona]

FYI the Github link is currently broken.

[@RichardEisenberg-JS]

It seems to work for me, even when I log out. Looks like YT redirects to snag some analytics; maybe that's the problem somehow? If you search for "Jane Street opam repository", you'll find it. You might need to follow a link at the bottom to get our compiler extensions; should be hopefully clear from context.

[@jugsma6676]

Now, i think it's fixed

[@moonbird2266]

What an awesome video!

[@adicide9070]

you trying to do some rust here now?

[@RichardEisenberg-JS]

Well, yes! Rust is an inspiration for what we're up to, but we're not trying to mimic it directly. Instead, we see how Rust uses lifetimes to effectively allow stack allocation, and we want that, too. :)

[@adicide9070]

@@RichardEisenberg-JS, sure, I get it. but as a dude that is trying to get into ML, with OCaml already being a hard sell -- queries like "Why Ocaml sucks" bring up interesting, if sometimes outdated, results -- it looks a bit cumbersome to throw this in the mix. just like the sentence I just wrote, inadvertently!

[@RichardEisenberg-JS]

@@adicide9070 Makes sense. There's always a delicate balance between expressiveness and simplicity. We're hoping to gain experience by targeting primarily fellow Jane Streeters, figure out where the pain points are, and then try to make it so that all of this becomes simple. One nice bit of feedback I've gotten roaming the office is that some programmers here don't even really know what locals are -- that means that you can successfully use OCaml without knowing about this niche feature.

[@clementdato6328]

is this extension publicly available?

[@RichardEisenberg-JS]

Yes! Link is in the description.

[@jameslew7269]

all fun and games until you can't unpack GADTs bc they'll escape );

[@RichardEisenberg-JS]

Do you have an example? Should work fine with unpacking GADTs.

[@jameslew7269]

@@RichardEisenberg-JS i had an issue with unpacking GADTs where their type escaped the region. it works as intended but have to be careful bc so many ways fail. which is good since thats partially why local_ is there, to spot mistakes