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That's exactly why Zig is such an interesting language to me. The premise of trying to write a modern C replacement - essentially what C would be if it were de

by skohan 5y ago

That's exactly why Zig is such an interesting language to me. The premise of trying to write a modern C replacement - essentially what C would be if it were designed with the learnings of the past 40 years in mind - is super exciting. I am a fan of Rust, but I am not 100% sold on it. The safety features and ADT's are nice, but I find it quite clunky in practice, and it is just such a huge language full of so many features. It almost feels more like a test language to try the concept of static memory management than a properly designed language in some ways. I feel it's missing the quality from C/C++ that they are a very thin abstraction over assembly.

eropple 5y ago
I haven't looked at Zig much because I mostly noodle with lower-level languages with an eye towards game prototypes and the like, so I don't know much about it. Have anything you'd recommend reading about the language?
- cturtle 5y ago
  I like Zig because it feels like a refinement of C with all the knowledge of the years since C was created. Some of my favorite features are no global allocator, well-defined pointers (with optionals required for nullability), generics and partial evaluation at compile-time, and builtin features/functions for all sorts of operations that are only extensions in C/C++ like SIMD and packed structs. Read [0] for a comparison among Zig, D, Rust, and C++, and read [1] for a deeper look at the language's goals. I personally really love Zig's type system [2], with a system for generics that is very simple and consistent. [0]: https://ziglang.org/learn/why_zig_rust_d_cpp/ https://ziglang.org/learn/why_zig_rust_d_cpp/ [1]: https://ziglang.org/learn/overview/ https://ziglang.org/learn/overview/ [2]: https://nathancraddock.com/blog/consistency-in-zigs-type-system/ https://nathancraddock.com/blog/consistency-in-zigs-type-sys...
  - eropple 5y ago
    I'm going to give those a read. Thanks!
Aloha 5y ago
I've always understood that C was designed to fit a hardware budget. We knew about many of these features then, when C was created - but it wasn't until the 2000's really where computing horsepower caught up to be able to use them in a universal way.
- skohan 5y ago
  Hmm I've always thought of C in terms of "portable assembly". Not so much that features were omitted because they weren't performant enough, but because they strayed too far away from machine-primitive operations.
  - eropple 5y ago
    C itself is pretty far from the machine, too, except by accident.
- nicoburns 5y ago
  Some of them would have been great even on 70s hardware. Proper array, slice and string types come to mind.
nindalf 5y ago
> a very thin abstraction over assembly. I think this statement implies that it’s clear and obvious what assembly will be generated from a snippet of C/C++ code. But few people can understand everything that optimising compilers and modern processors do to normal looking code. An example of this lack of knowledge is seeing people disagree on if a snippet contains UB or not. If C is so simple, why do people struggle to write it?
- skohan 5y ago
  > But few people can understand everything that optimising compilers and modern processors do to normal looking code. Well when I'm talking about an abstraction over assembly I'm not talking about optimizing compilers. That's another topic entirely. What I mean is, if you look at a block of C code, it's very easy to understand what the machine is doing. > If C is so simple, why do people struggle to write it? Do they? I think people struggle to write correct, bug-free code in C, but that's because it doesn't save you from yourself, and it's happy to let you do whatever the hardware will do. That's a much larger programmable space than the set of all safe correct programs. But I don't think people in general have difficulty looking at a snippet of C code and understanding it.
  - nindalf 5y ago
    > What I mean is, if you look at a block of C code, it's very easy to understand what the machine is doing. So they simultaneously understand what the machine is doing but don’t know what assembly will be generated? Both can’t be true. If everyone understood what the machine was doing, everyone would be able to look at a snippet and agree - “that’s UB, let’s not do that”. But they can’t agree. Because few people understand what the compiler and the processor will do. The “thin layer of assembly” was true for the first generation of C compilers. But it hasn’t been true for a long time. It’s a complete black box now. Anyone who thinks that it’s straightforward isn’t being upfront with themselves.
    - skohan 5y ago
      > So they simultaneously understand what the machine is doing but don’t know what assembly will be generated? Both can’t be true. I mean I can understand a reasonable mapping to what the un-optimized assembly would be. Compiler optimization is very complex, and is going to obscure the results in every language. > If everyone understood what the machine was doing, everyone would be able to look at a snippet and agree - “that’s UB, let’s not do that”. But they can’t agree. Because few people understand what the compiler and the processor will do. What? I think everyone can agree that UB is much harder to detect in assembly than in higher level languages than assembly, and assembly gives the most clear view of what the machine is doing. It's a very complex topic to create a system which detects and disallows UB automatically in the compiler - this requires a lot more complexity than a simple mapping of high level instructions to machine instructions. > The “thin layer of assembly” was true for the first generation of C compilers. But it hasn’t been true for a long time. It’s a complete black box now. Anyone who thinks that it’s straightforward isn’t being upfront with themselves. I don't know, seems pretty straightforward to me: https://godbolt.org https://godbolt.org
pcwalton 5y ago
C and C++ are not a very thin abstraction over assembly language. The C virtual machine is very far from the actual hardware. And Rust is the same distance from the hardware as C and C++ are. Rust's core operations are, by and large, the same simple mapping to LLVM instructions. I don't find the idea of a new non-memory-safe C replacement in 2022 very exciting. We should be moving away as an industry from non-memory-safe languages, for the obvious security and productivity reasons.
- skohan 5y ago
  I don't see how you could argue that C is comparable in terms of level of abstraction to Rust and C++. For instance with Rust memory management is totally abstracted away from you as the programmer, which is a core part of what a computer is doing. And if you index into an array in C, that's basically like saying `root memory location + stride * index`. In Rust it's calling a trait function which could be doing arbitrary work. Rust and C++ are on similar levels of abstraction, but C is much, much simpler.
  - pcwalton 5y ago
    How is Rust memory management totally abstracted away from you? You have to opt in to every heap allocation, just as you have to call malloc() in C. And it's certainly true that Rust has overloading and C doesn't, but that wasn't what I was getting at. The point is that C is defined in terms of the C virtual machine, not the underlying hardware. The C virtual machine is quite far from the actual CPU instructions.
    - skohan 5y ago
      In Rust you opt into every heap allocation with an abstraction like Rc, Arc, Box etc. With C you would have to implement each of those behaviors with primitives, because C is at a lower level of abstraction than Rust.
      - djur 5y ago
        malloc is also an abstraction.
pjmlp 5y ago
You mean the learnings of Modula-2 in 1978, but with a C like syntax?

by skohan 5y ago

eropple 5y ago

I haven't looked at Zig much because I mostly noodle with lower-level languages with an eye towards game prototypes and the like, so I don't know much about it. Have anything you'd recommend reading about the language?

cturtle 5y ago
I like Zig because it feels like a refinement of C with all the knowledge of the years since C was created. Some of my favorite features are no global allocator, well-defined pointers (with optionals required for nullability), generics and partial evaluation at compile-time, and builtin features/functions for all sorts of operations that are only extensions in C/C++ like SIMD and packed structs. Read [0] for a comparison among Zig, D, Rust, and C++, and read [1] for a deeper look at the language's goals. I personally really love Zig's type system [2], with a system for generics that is very simple and consistent. [0]: https://ziglang.org/learn/why_zig_rust_d_cpp/ https://ziglang.org/learn/why_zig_rust_d_cpp/ [1]: https://ziglang.org/learn/overview/ https://ziglang.org/learn/overview/ [2]: https://nathancraddock.com/blog/consistency-in-zigs-type-system/ https://nathancraddock.com/blog/consistency-in-zigs-type-sys...
- eropple 5y ago
  I'm going to give those a read. Thanks!

Aloha 5y ago

I've always understood that C was designed to fit a hardware budget. We knew about many of these features then, when C was created - but it wasn't until the 2000's really where computing horsepower caught up to be able to use them in a universal way.

skohan 5y ago
Hmm I've always thought of C in terms of "portable assembly". Not so much that features were omitted because they weren't performant enough, but because they strayed too far away from machine-primitive operations.
- eropple 5y ago
  C itself is pretty far from the machine, too, except by accident.
nicoburns 5y ago
Some of them would have been great even on 70s hardware. Proper array, slice and string types come to mind.

nindalf 5y ago

> a very thin abstraction over assembly. I think this statement implies that it’s clear and obvious what assembly will be generated from a snippet of C/C++ code. But few people can understand everything that optimising compilers and modern processors do to normal looking code. An example of this lack of knowledge is seeing people disagree on if a snippet contains UB or not. If C is so simple, why do people struggle to write it?

skohan 5y ago
> But few people can understand everything that optimising compilers and modern processors do to normal looking code. Well when I'm talking about an abstraction over assembly I'm not talking about optimizing compilers. That's another topic entirely. What I mean is, if you look at a block of C code, it's very easy to understand what the machine is doing. > If C is so simple, why do people struggle to write it? Do they? I think people struggle to write correct, bug-free code in C, but that's because it doesn't save you from yourself, and it's happy to let you do whatever the hardware will do. That's a much larger programmable space than the set of all safe correct programs. But I don't think people in general have difficulty looking at a snippet of C code and understanding it.
- nindalf 5y ago
  > What I mean is, if you look at a block of C code, it's very easy to understand what the machine is doing. So they simultaneously understand what the machine is doing but don’t know what assembly will be generated? Both can’t be true. If everyone understood what the machine was doing, everyone would be able to look at a snippet and agree - “that’s UB, let’s not do that”. But they can’t agree. Because few people understand what the compiler and the processor will do. The “thin layer of assembly” was true for the first generation of C compilers. But it hasn’t been true for a long time. It’s a complete black box now. Anyone who thinks that it’s straightforward isn’t being upfront with themselves.
  - skohan 5y ago
    > So they simultaneously understand what the machine is doing but don’t know what assembly will be generated? Both can’t be true. I mean I can understand a reasonable mapping to what the un-optimized assembly would be. Compiler optimization is very complex, and is going to obscure the results in every language. > If everyone understood what the machine was doing, everyone would be able to look at a snippet and agree - “that’s UB, let’s not do that”. But they can’t agree. Because few people understand what the compiler and the processor will do. What? I think everyone can agree that UB is much harder to detect in assembly than in higher level languages than assembly, and assembly gives the most clear view of what the machine is doing. It's a very complex topic to create a system which detects and disallows UB automatically in the compiler - this requires a lot more complexity than a simple mapping of high level instructions to machine instructions. > The “thin layer of assembly” was true for the first generation of C compilers. But it hasn’t been true for a long time. It’s a complete black box now. Anyone who thinks that it’s straightforward isn’t being upfront with themselves. I don't know, seems pretty straightforward to me: https://godbolt.org https://godbolt.org

pcwalton 5y ago

C and C++ are not a very thin abstraction over assembly language. The C virtual machine is very far from the actual hardware. And Rust is the same distance from the hardware as C and C++ are. Rust's core operations are, by and large, the same simple mapping to LLVM instructions. I don't find the idea of a new non-memory-safe C replacement in 2022 very exciting. We should be moving away as an industry from non-memory-safe languages, for the obvious security and productivity reasons.

skohan 5y ago
I don't see how you could argue that C is comparable in terms of level of abstraction to Rust and C++. For instance with Rust memory management is totally abstracted away from you as the programmer, which is a core part of what a computer is doing. And if you index into an array in C, that's basically like saying `root memory location + stride * index`. In Rust it's calling a trait function which could be doing arbitrary work. Rust and C++ are on similar levels of abstraction, but C is much, much simpler.
- pcwalton 5y ago
  How is Rust memory management totally abstracted away from you? You have to opt in to every heap allocation, just as you have to call malloc() in C. And it's certainly true that Rust has overloading and C doesn't, but that wasn't what I was getting at. The point is that C is defined in terms of the C virtual machine, not the underlying hardware. The C virtual machine is quite far from the actual CPU instructions.
  - skohan 5y ago
    In Rust you opt into every heap allocation with an abstraction like Rc, Arc, Box etc. With C you would have to implement each of those behaviors with primitives, because C is at a lower level of abstraction than Rust.
    - djur 5y ago
      malloc is also an abstraction.

pjmlp 5y ago

You mean the learnings of Modula-2 in 1978, but with a C like syntax?