Chris Lattner on garbage collection vs. Automatic Reference Counting (2017)

Re:Chris Lattner on garbage collection vs. Automatic Referen... by pphysch on Sunday April 24, 2022 @01:33AM (#31141536)

Consider the common pattern:

    with open(path) as file:
        result = func(file.read())

    another_func(result)

If `with` used a separate scope then it would be a lot less ergonomic. How might we bring data outside that scope and be confident that `with` isn't forcibly cleaning things up? Would be a lot more verbose.

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Re:Chris Lattner on garbage collection vs. Automatic Referen... by shakna on Sunday April 24, 2022 @01:49AM (#31141593)

I think you've missed what I've meant by a new binding. That the body executes is entirely intuitive.

However:

    with open(path) as file:
        ...

    if file.mode == 'r':
        print("Huh? file is still a thing?")

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Re:Chris Lattner on garbage collection vs. Automatic Referen... by xscott on Sunday April 24, 2022 @04:07AM (#31142135)

Python doesn't have block scope, but most people don't seem to notice:

    def foo():
        if False:
             x = 123
        print("x is visible out here:", x)

That will generate an error because `x` is "referenced before assignment", but the variable exists for the entire function. This can bite you in subtle ways:

    x = "is global out here"
    def foo():
         print("all good:", x)

    def bar():
         print("not good:", x)
         if False:
              x = "now x is local, even before this declaration"

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