I think I agree with what you're getting at, though I usually phrase it differently: indirection is not abstraction. A good abstraction makes it easier to understand what the code is doing by letting you focus on the important details and ignore the noise. It does this by giving you tools that match your problem space, whatever it may be. This will necessarily involve some amount of indirection when you switch semantic levels, but that's very different from constantly being told "look over there" when you're trying to figure out what the code is saying.

I’m familiar with spaghetti code and with lasagna code (too many layers) but I’m curious: what’s ravioli code?

This long post is demonstrating that Knuth’s advice, “premature optimization is the root of all evil,” is still one of the first heuristics you should apply.

The article describes a couple of straw men and even claims that they’re right in principle:

> Then someone on the team raises an eyebrow. “Isn’t that an extra function call? Indirection has a cost.” Another member quickly nods.

> They’re not wrong in principle.

But they are wrong in principle. There’s no excuse for this sort of misinformation. Anyone perpetuating it, including the blog author, clearly has no computer science education and shouldn’t be listened to, and should probably be sent to a reeducation camp somewhere to learn the basics of their profession.

Perhaps they don’t understand what a compiler does, I don’t know, but whatever it is, they need to be broken down and rebuilt from the ground up.

I think it’s making a case that normally you shouldn’t even bother benchmarking it, unless you know that it’s in a critical hot path.

I'm not sure Rust's `async fn` desugaring (which involves a data structure for the state machine) is inlineable. (To be precise: maybe the desugared function can be inlined, but LLVM isn't allowed to change the data structure, so there may be extra setup costs, duplicate `Waker`s, etc.) It's probably true that there is a performance cost. But I agree with the article's point that it's generally insignificant.

For non-async fns, the article already made this point:

> In release mode, with optimizations enabled, the compiler will often inline small extracted functions automatically. The two versions — inline and extracted — can produce identical assembly.

I strongly prefer this sort of code:

```

    fn does_a_many_step_process():

         first_step_result_which_is_not_tied_to_details_internal_to_the_step_implementation = well_named_first_step_which_encapsulates_concerns();



        second_step_result_in_same_manner = well_named_second_step_which_encapsulates_concerns();

  ...etc

} ```

The logic of process flow is essentially one kind of information. All the implementation details are another. Step functions should not hide further important steps - they should only hide hairy implementation details that other steps don't need to know about.

One huge one is so that you can test it in isolation.

There's extraction for reuse and then theres extraction for readability/maintainability. The second largely comes down to personal taste. I personally tend to lose the signal in the noise, so it's easy for me to follow the logic if some of the larger bits are pushed into appropriately named functions. Goes to the whole self commenting code thing. I know there's a chunk of code behind that function call, I know it does some work based on its name and args, but I don't have to worry about it in the moment. There's a limit of course, moving a couple lines of code out without good cause is infuriating.

Other people prefer to have big blocks of code together in one place, and that's fine too. It just personally makes it harder for me to track stuff.

The idea is that performance isn’t a reason not to do it. Other considerations may cause you to choose inline, but performance shouldn’t be one of them.

I don't see anything wrong code-wise, but it's definitely an odd way of making an accumulator. Maybe I'm pedantic

People new to Rust sometimes assume every abstraction is free but that's just not the case, especially with lifetimes and dynamic dispatch. Even a small function call can hide allocations or vtable lookups that add up quickly if you're not watching closely.

Did you read the article? The author makes exactly that point.