Comment by arghwhat
1 month ago
> The C language also does not specify a linked list. Go tell your developer friends that C can never use a linked list.
They would not blink because the statement is accurate. To the C language and to the C compiler, there are no linked lists - just random structs with random pointers pointing to god knows what. C does know about arrays though.
> The JavaScript spec[1] does not [specify garbage collection].
I have good reason to believe that you are not familiar with the specification, although to be fair most developers would not be familiar with its innards.
The specification spends quite a while outlining object liveness and rules for when garbage is allowed to be collected. WeakRefs, FinalizationRegistries, the KeptObjects list on the agent record, ...
Just like with Go, it is perfectly valid to have an implementation of a "garbage collector" that is a no-op that never collects anything, which means that the application will continously leak memory until it runs out and crashes as the language provides no mechanism to free memory - for Go, you can switch to this with `GOGC=off`. The specific wording from ECMA-262:
> This specification does not make any guarantees that any object or symbol will be garbage collected. Objects or symbols which are not live may be released after long periods of time, or never at all. For this reason, this specification uses the term "may" when describing behaviour triggered by garbage collection.
If you're not used to reading language specs the rest of the details can be a bit dry to extract, but the general idea is that the spec outlines automatic allocation, permission for a runtime to deallocate things that are not considered "live", and the rules under which something is considered to be "live". And importantly, it provides no means within the language to take on the task of managing memory yourself.
This is how languages specify garbage collection as the language does not want to limit you to a specific garbage collection algorithm, and only care about what the language needs to guarantee.
> [1] The standard calls itself ECMAScript, but I believe your intent here is understood.
sigh.
> For what it is worth, I also put "C can never use a garbage collector" into an LLM. It also called me out on that bullshit just the same.
more sigh. LLMs always just wag their tails when you beg the question on an opinion. They do not do critical thinking for you or have any strong opinions to give of their own.
I'm done, have a nice day.
> To the C language and to the C compiler, there are no linked lists
But are most certainly able to use one. Just as they can use a garbage collector. You are quite right that these are not provided out of the box, though. If you want to use them, you are on your own. Both Limbo and Rust do provide a garbage collector to use out of the box, though, so that's something different.
> The specification spends quite a while outlining object liveness and rules for when garbage is allowed to be collected. WeakRefs, FinalizationRegistries, the KeptObjects list on the agent record, ...
But, again, does not specify use of a garbage collector. It could use one, or not. That is left up to the implementer.
> it is perfectly valid to have an implementation of a "garbage collector" that is a no-op that never collects anything
It's perfectly valid as far as the computer is concerned, but in the case of Go not spec-compliant. Obviously you don't have to follow the spec. It is not some fundamental law of the universe. But if you want to be complaint, that is not an option. I get you haven't actually read the spec, but you didn't have to either as this was already explained in the earlier comment.
> This is how languages specify garbage collection
That is how some languages specify how you could add garbage collection if you so choose. It is optional, though. At very least you can always leak memory. Go, however, explicitly states that it is garbage collected, always. An implementation of Go that is GC-less and leaks memory, while absolutely possible to do and something the computer will happily execute, does not meet the conditions of the spec.
> I'm done
Done what? It is not clear what you started.