Four Years of Rust

Re:Four Years of Rust by manwe150 on Wednesday May 15, 2019 @11:00PM (#19925781)

Not exactly a systems language, but Python has deterministic destruction (due to the use of reference counting) of non-cyclic data structures.

Edit: Oh, and if you don’t think that’s enough, note that Rust doesn’t guarantee destruction to ever occur in that case (“considered safe”): https://doc.rust-lang.org/book/ch15-06-reference-cycles.html

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Re:Four Years of Rust by kevinmgranger on Wednesday May 22, 2019 @11:57AM (#19982550)

> Python has deterministic destruction

Not quite.

https://docs.python.org/3/reference/datamodel.html#object.__...

> It is not guaranteed that __del__() methods are called for objects that still exist when the interpreter exits.

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Re:Four Years of Rust by dpc_pw on Thursday May 16, 2019 @12:41AM (#19926175)

Oh, interesting. But from what I read it's only an implementation detail of CPython?

With `with`I can't eg. pass an open file to another function to eg. be closed there etc.

Example:

https://play.rust-lang.org/?version=stable&mode=debug&editio...

closing `File` will happen at the end of `foo` or `foo2`.

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Re:Four Years of Rust by manwe150 on Thursday May 16, 2019 @12:21PM (#19930360)

That's probably a tricky question, since CPython is also essentially the spec. PyPy talks a bit about this: http://doc.pypy.org/en/latest/cpython_differences.html#diffe...

That's true, since Python has reflection it can't easily optimize that case, whereas that's a powerful benefit of having a linear type system for tracking ownership like Swift or Rust. But early freeing (which Rust has and Python does not) is slightly different from deterministic freeing (which both have) is slightly different from guaranteed freeing (which CPython has and Rust does not).

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