3 ms·

To add to this, Java and other GC languages in some sense have manual memory management too, no matter how much we like to pretend otherwise. It's easy to fall

To add to this, Java and other GC languages in some sense have manual memory management too, no matter how much we like to pretend otherwise. It's easy to fall into a trap where your Banana class becomes a GorillaHoldingTheBananaAndTheEntireJungle class(to borrow a phrase from Joe Armstrong), and nothing ever gets freed because everything is always referenced by something else. Not to mention the dark arts of avoiding long GC pauses etc. It's possible to do this in rust too, I suppose. The clearest difference is that in rust these things are explicit rather than implicit. To do this in rust you'd have to use 'static, etc. The other distinction is compile-time versus runtime, of course.

mattashii 1y ago
> The clearest difference is that in rust these things are explicit rather than implicit. To do this in rust you'd have to use 'static, etc. You could use 'static, or you can move (partial) ownership of an object into itself with Rc/Arc and locking, causing the underlying counter to never return to 0. It's still very possible to accidentally hold on to a forest.
Bratmon 1y ago
> It's easy to fall into a trap where your Banana class becomes a GorillaHoldingTheBananaAndTheEntireJungle class(to borrow a phrase from Joe Armstrong), and nothing ever gets freed because everything is always referenced by something else. Can you elaborate on this? I'm struggling to picture a situation in which I have a gorilla I'm currently using, but keeping the banana it's holding and the jungle it's in alive is a bad thing.
- lmm 1y ago
  The joke is you're using the banana but you didn't actually want the gorilla, much less the whole jungle. E.g. you might have an object that represents the single database row you're doing something with, but it's keeping alive a big result set and a connection handle and a transaction. The same thing happening with just an in-memory datastructure (e.g. you computed some big tree structure to compute the result you need) is less bad, but it can still impact your memory usage quite a lot.
BananaaRepublik 1y ago
On the topic of being explicit, why is it pub/pub(crate) rather than pub(extern)/pub?
- Measter 1y ago
  pub(crate) came later. I think it's something an edition could change, but I don't remember seeing people suggest it.

mattashii 1y ago

> The clearest difference is that in rust these things are explicit rather than implicit. To do this in rust you'd have to use 'static, etc. You could use 'static, or you can move (partial) ownership of an object into itself with Rc/Arc and locking, causing the underlying counter to never return to 0. It's still very possible to accidentally hold on to a forest.

Bratmon 1y ago

> It's easy to fall into a trap where your Banana class becomes a GorillaHoldingTheBananaAndTheEntireJungle class(to borrow a phrase from Joe Armstrong), and nothing ever gets freed because everything is always referenced by something else. Can you elaborate on this? I'm struggling to picture a situation in which I have a gorilla I'm currently using, but keeping the banana it's holding and the jungle it's in alive is a bad thing.

lmm 1y ago
The joke is you're using the banana but you didn't actually want the gorilla, much less the whole jungle. E.g. you might have an object that represents the single database row you're doing something with, but it's keeping alive a big result set and a connection handle and a transaction. The same thing happening with just an in-memory datastructure (e.g. you computed some big tree structure to compute the result you need) is less bad, but it can still impact your memory usage quite a lot.

BananaaRepublik 1y ago

On the topic of being explicit, why is it pub/pub(crate) rather than pub(extern)/pub?

Measter 1y ago
pub(crate) came later. I think it's something an edition could change, but I don't remember seeing people suggest it.