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A comment on A Python Interpreter Written in Rust. Parent comment

Re:A Python Interpreter Written in Rust by eridius on Saturday February 02, 2019 @10:27PM (#19067643)
I'm pretty rusty on Python but my impression wasn't that the GIL meant just "no data races" but that it also meant "data can't change out from under you in the middle of executing a statement". You could write a Python interpreter that ensured no data races and yet still had divergent behavior by allowing shared data to be mutated by another thread halfway through executing a statement.
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Re:A Python Interpreter Written in Rust by pdonis on Sunday February 03, 2019 @12:00AM (#19067959)
> my impression wasn't that the GIL meant just "no data races" but that it also meant "data can't change out from under you in the middle of executing a statement".

That's not quite what the GIL guarantees. It guarantees that data can't change out from under you in the middle of executing a bytecode. But many Python statements (and expressions) do not correspond to single bytecodes.

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