nimforum mirror - A question for owned ref

polezhang (orginal) [2025-02-05T11:45:51+01:00] view original

As RFC https://github.com/nim-lang/RFCs/issues/144 stated , code below should abort, but the program runs successfully ,why ? How owned ref cowork with GC ?

type

Node = ref object: data: int

var dangling : Node = nil

block:: var x = Node(data: 3) # inferred to be an owned ref dangling = x # unowned ref assert dangling.data == 3 x = Node(data: 4) # destroys x! But x has dangling refs --> abort.

echo "end!"

active boot switches: -d:release

Hint: used config file 'E:Toolsnimconfignim.cfg' [Conf] Hint: used config file 'E:Toolsnimconfigconfig.nims' [Conf] Hint: mm: orc; threads: on; opt: speed; options: -d:release 10541 lines; 0.021s; 10.562MiB peakmem; proj: E:codenimsrctestsrctest.nim; out: E:codenimsrctestsrctest.exe [SuccessX] Hint: E:codenimsrctestsrctest.exe --verbose [Exec] end!

Araq (orginal) [2025-02-05T14:18:15+01:00] view original

I marked this RFC as "rejected" in order to make it clear. owned ref is now an annotation that is ignored and there are no plans of reviving it. This work has been succeeded in favour of mm:arc.

If you want "ownership you can count on" you can still get this with a custom smart pointer type.

polezhang (orginal) [2025-02-05T15:19:22+01:00] view original

OK, and as a beginner in Nim with some knowledge of C++ and Rust, it is important for me to understand the language features through RFCs.

Thanks for your time @Araq

crfout (orginal) [2025-02-05T15:49:00+01:00] view original

Perhaps try reading the documentation first, before going to an RFC? Most of it is really quite decent.

https://nim-lang.org/documentation.html https://nim-lang.org/docs/manual.html https://nimprogrammingbook.com/

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