4 ms·

Zig's "zip" is purely syntactical, where Python's zip is a generator. This is significant both in terms of performance (Zig wins) and flexibility (Python wins)

by klyrs 4y ago

Zig's "zip" is purely syntactical, where Python's zip is a generator. This is significant both in terms of performance (Zig wins) and flexibility (Python wins). Unlike Python, you can't pass a zip generator around. It's just a for-loop. While zig loops are expressions, they only return a single value.

masklinn 4y ago
> This is significant both in terms of performance (Zig wins) Does it, actually? Does Zig's built-in pseudo-zip outperform Rust's? Or C++23's? > It's just a for-loop. Except it's not "just" a for loop, it's a weird special case for a for loop. And one which is actively dangerous too.
- klyrs 4y ago
  Please check the context, I was comparing to Python. And please chill out. It's only "dangerous" when you decide to run it that way.
  - masklinn 4y ago
    [flagged]
    - klyrs 4y ago
      Hi, no need to be so abrasive about it. > Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith. Python's zip function returns a generator. A generator in zig would look like a function pointer with a closure. If zig were to implement the Python-style "zip" function, constructing the closure, and iterating over the generator, would be significantly slower than the naked "just a for loop" that we see in TFA. And that's not even considering the tuple construction (oops, now we need an allocator) & unpacking. Ergo, the zig-style "syntactical zip" is higher performance than the Python-style "functional zip". Even when you cut through the baseline performance differences between the languages.
      - masklinn 4y ago
        > Hi, no need to be so abrasive about it. That's just projection. > Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith. I'll get right on that as soon as you extend the same courtesy, which you have refused to do at every opportunity.
    - deleted 4y ago
      [deleted]
- judofyr 4y ago
  > Except it's not "just" a for loop, it's a weird special case for a for loop. You could also argue that a for loop which can only iterate over a _single_ sequence is a special case of a multi-sequence for loop. > And one which is actively dangerous too. In safe builds (ReleaseSafe, Debug) it will cause a controlled panic if the sequences are not of the same size. Most likely it's a logical bug if you iterate over two sequences of different sizes. In ReleaseFast the compiler will make assumptions to improve performance. If it's very important for your code you can force a certain code block to always have runtime safety. Yes, there are trade-offs, but I don't feel it's _unreasonable_.
  - lmm 4y ago
    > You could also argue that a for loop which can only iterate over a _single_ sequence is a special case of a multi-sequence for loop. When a "for loop" in virtually every language is not multi-sequence, not really. People expect a "for loop" to be a certain kind of thing.

by klyrs 4y ago

masklinn 4y ago

> This is significant both in terms of performance (Zig wins) Does it, actually? Does Zig's built-in pseudo-zip outperform Rust's? Or C++23's? > It's just a for-loop. Except it's not "just" a for loop, it's a weird special case for a for loop. And one which is actively dangerous too.

klyrs 4y ago
Please check the context, I was comparing to Python. And please chill out. It's only "dangerous" when you decide to run it that way.
- masklinn 4y ago
  [flagged]
  - klyrs 4y ago
    Hi, no need to be so abrasive about it. > Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith. Python's zip function returns a generator. A generator in zig would look like a function pointer with a closure. If zig were to implement the Python-style "zip" function, constructing the closure, and iterating over the generator, would be significantly slower than the naked "just a for loop" that we see in TFA. And that's not even considering the tuple construction (oops, now we need an allocator) & unpacking. Ergo, the zig-style "syntactical zip" is higher performance than the Python-style "functional zip". Even when you cut through the baseline performance differences between the languages.
    - masklinn 4y ago
      > Hi, no need to be so abrasive about it. That's just projection. > Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith. I'll get right on that as soon as you extend the same courtesy, which you have refused to do at every opportunity.
  - deleted 4y ago
    [deleted]
judofyr 4y ago
> Except it's not "just" a for loop, it's a weird special case for a for loop. You could also argue that a for loop which can only iterate over a _single_ sequence is a special case of a multi-sequence for loop. > And one which is actively dangerous too. In safe builds (ReleaseSafe, Debug) it will cause a controlled panic if the sequences are not of the same size. Most likely it's a logical bug if you iterate over two sequences of different sizes. In ReleaseFast the compiler will make assumptions to improve performance. If it's very important for your code you can force a certain code block to always have runtime safety. Yes, there are trade-offs, but I don't feel it's _unreasonable_.
- lmm 4y ago
  > You could also argue that a for loop which can only iterate over a _single_ sequence is a special case of a multi-sequence for loop. When a "for loop" in virtually every language is not multi-sequence, not really. People expect a "for loop" to be a certain kind of thing.