Is it just me, or does Rust feel much more bare-bones than other languages? I just started learning it recently and this is the one thing that stood out to me, much more so than the memory management business. A lot of things that would normally be part of the language has to be achieved through meta-programming in Rust.

Is this a deliberate design choice? What do we gain from this setup?

Edits:

  1. Somehow, this question is being interpreted as a complaint. It’s not a complaint. As a user, I don’t care how the language is designed as long as it has a good user experience, but the curious part of my mind always wants to know why things are the way they are. Maybe another way to phrase my question: Is this decision to rely more on meta-programming responsible for some of the good UX we get in Rust? And if so, how?
  2. I’m using meta-programming to mean code that generates code in the original language. So if I’m programming in Rust, that would be code that generate more Rust code. This excludes compilation where Rust gets converted into assembly or any other intermediate representation.
  • anton@lemmy.blahaj.zone
    3·
    1 day ago

    You can design a language where you don’t need to generate code to accomplish this.

    Other people have python scripts generate C, so having on in the same codebase and language is certainly an improvement.

    My question isn’t why this is necessary in Rust. My question is why Rust was designed such that this was necessary.

    Because otherwise the compiler team either also needs to maintain a huge amount libraries or cut corners and move things to runtime that really should happen at compile time.

    Someone mentioned elsewhere that this allows for compile-time type safety. I’m still trying to wrap my head around how that works.

    printf is a great example. According to the C type system, it takes a string and a variable amount of untyped arguments dependent on the content of the string, but that doesn’t actually describe the allowed arguments.
    Misusing printf like this printf("%s", 42); will get you a warning, but only because there is a special case for printf in the compiler. If you have your own function that does the same as printf, and you misuse the same way, you will find out by dissecting the core dump.

    In rust the format string gets parsed at compile time by a macro, which decides the type of each arguments that can than be checked by the compiler. Imagine printf(“%s %d”,…) created a function with the signature specialized_printf(char* agr0, int arg1), it would be impossible to pass the wrong types of arguments.

    Now that these tools exist people have gone further and made a library that checks SQL queries against the shema of a running database and causes a compile error if it doesn’t fit.