C++20 Improved the For-Loop Syntax

Post by foldr » Wed, Jul 15, 2026, 8:01 AM UTC

hnisnotbenign wrote: post #38

adityamwagh wrote: post #11

> It seems to me that the C++ Standards Committee is doing a decent job maintaining the language, and introducing useful features when it makes sense to do so. This can’t be further from truth. C++ is essentially Frankenstein’s monster.

I believe one of the main goals of whatever shadowy organizations are behind the "standards committee" is to sabotage the language to help clear the way for Rust. If these people really have a great idea for what the future C++ should be like, then they should introduce that language all at once. Let us see their grand vision in one big package that can be embraced or rejected. This steady drip-drip-drip of half-bake…

    if (max)

    void WasmShuffleAnalyzer::TryReduceFromMSB(OpIndex input,
                                               const Simd128ShuffleOp& shuffle,
                                               uint8_t lower_limit,
                                               uint8_t upper_limit) {
      DemandedBytes demanded = GetDemandedBytes(&shuffle);
      std::optional max = {};
      for (unsigned i = 0; i = lower_limit && index (index % kSimd128Size),
                         max.value_or(uint8_t{0}));
        }
      }
      if (max) {
        // input can be reduced.
        TRACE("Can reduce Op %d based upon max used index: %d\n", input.id(),
              max.value());
        demanded_byte_analysis_.Add(
            input, DemandedBytes::LowFromMaxShuffleIndex(max.value()));
      }
    }

Post by rjh29 » Wed, Jul 15, 2026, 8:34 AM UTC

petilon wrote: post #5

fourseventy wrote: post #4

Just what C++ needs, more bloat lol.

C++ is probably the only language that needs a strong style guide, to define a subset you are allowed to use in the project. Linus Torwalds famously said that subset is zero. You're not allowed to use C++ in Linux, a wise move. Here's Google's: https://google.github.io/styleguide/cppguide.html Search for "do not use" and you'll find plenty of hits.

Post by pwdisswordfishq » Wed, Jul 15, 2026, 8:55 AM UTC

senkora wrote: post #42

UncleOxidant wrote: post #23

Reading this, I really can't make much sense of it: for (int i=0; auto&& it: vec) cout It's certainly not obvious what's going on there at a glance. This is at least a bit more pythonic: for (auto [i, it] : std::views::enumerate(vec)) { std::cout

The part that confuses me is that they use “it” to name a variable that is not actually an iterator. That’s very bad style. I would name it “s”.

Post by pjmlp » Wed, Jul 15, 2026, 9:12 AM UTC

    int main() {
        vector vec = { 
            "the", "quick", "brown", "fox", 
            "jumped", "over", "the", "lazy", "dog" 
        };

        for (auto&& [i, it] : vec | std::views::enumerate)
            println ("{}:{}", ++i, it);
    }

Post by pjmlp » Wed, Jul 15, 2026, 9:16 AM UTC

WalterBright wrote: post #40

HarHarVeryFunny wrote: post #2

C++20 also has an enumerate() generator, so if you like the python syntax you can just do: for (auto [i,v] : std::views::enumerate(vec)) std::cout FWIW C++23 also has a python-like print and println: std::println("{}: {}", i, v);

> std::cout C++ needs to abandon iostreams. Didn't the C++ community acknowledge that it was a bad idea? In the early days of D, people did want to do a version of it for D, but I objected and currently nobody wants it.