Interview with Zig language creator Andrew Kelley [video] • Hacker News Board

Re: Interview with Zig language creator Andrew Kelley [video]

#191

Post by elcritch » Sat, Aug 29, 2020, 12:08 AM UTC

pron wrote: post #183

elcritch wrote: post #164

Earlier quoted context omitted.

Look at any sufficiently complex and/or low level C like Linux or FreeRTOS, and C text macros are used significantly. Some of the functionality would be horrible to implement otherwise. Being text based they're a pain, but like @gw, I'd have a hard time seeing a language like Zig without macros making a good low level system language. Maybe a good systems application like Kubernetes, similar to Go's niche, but not sy…

The goal isn't to have macros but to be able to do what macros are used for. Zig has found a different and simpler way to do what macros do. comptime gives you generic types, typeclasses/concepts, typesafe printf, conditional compilation and much more, all without macros and with a simpler construct than macros.

After reading your previous comment, I read a bit more about comptime. It does seem to be able to handle most of the cases I could think of wanting macros for, and it is a nice UX in that it's really like "bounded macros" and prevents building arbitrary new semantics. Though thinking on two levels in a given function does seem tricky to me, but perhaps that's just familiarity. Personally, I kind of like having separate macro vs code. Comptime seems like it'd almost be a better fit for Go than their generics proposal.

Re: Interview with Zig language creator Andrew Kelley [video]

#192

Post by smaddox » Sat, Aug 29, 2020, 1:53 AM UTC

pron wrote: post #2

I think that Zig's simplicity hides how revolutionary it is, both in design and in potential. It reminded me of my impression of Scheme when I first learned it over twenty years ago. You can learn the language in a day, but it takes a while to realize how exceptionally powerful it is. But it's not just its radical design that's interesting from an academic perspective; I also think that its practical goals align with…

I've been a financial backer of Zig for several months now, and plan to continue, because Andrew and the other contributers are pushing language design in directions that no other language is.

That being said, Zig's comptime is not a proper replacement for typeclasses/traits. Zig can do both comptime duck typing and vtable-based dispatch, but it cannot do proper bounded polymorphism type checking. It always fully evaluates types before type checking them. This might make it difficult (or impossible?) to provide type checking error messages of similar quality to Rust. I'm not sure if there are any other practical consequences for realistic programs, though. I suspect there might be issues around interface stability gaurantees, though I can't quite put my finger on why.

Re: Interview with Zig language creator Andrew Kelley [video]

#193

Post by pfg_ » Sat, Aug 29, 2020, 3:12 AM UTC

Oreb wrote: post #165

kristoff_it wrote: post #29

Earlier quoted context omitted.

If you want to be eased into the language, start by checking out https://ziglearn.org . Otherwise just take a look at the overview on the homepage of https://ziglang.org , then the docs. After that you should already be in great shape and you can read the standard library for examples of useful patterns.

Is the https://ziglearn.org site up to date with the latest versions of the language and standard library? The initial "Hello, World" example fails to compile for me. I get: Semantic Analysis [533/803] ./main.zig:4:14: error: container 'std.debug' has no member called 'print' std.debug.print("Hello, {}!\n", .{"World"});

It's the opposite - you have version 0.6.0, but the hello world there is for the latest master version of zig which can be downloaded at https://ziglang.org/download

Re: Interview with Zig language creator Andrew Kelley [video]

#194

Post by pron » Sat, Aug 29, 2020, 4:23 PM UTC

smaddox wrote: post #192

pron wrote: post #2

I think that Zig's simplicity hides how revolutionary it is, both in design and in potential. It reminded me of my impression of Scheme when I first learned it over twenty years ago. You can learn the language in a day, but it takes a while to realize how exceptionally powerful it is. But it's not just its radical design that's interesting from an academic perspective; I also think that its practical goals align with…

I've been a financial backer of Zig for several months now, and plan to continue, because Andrew and the other contributers are pushing language design in directions that no other language is. That being said, Zig's comptime is not a proper replacement for typeclasses/traits. Zig can do both comptime duck typing and vtable-based dispatch, but it cannot do proper bounded polymorphism type checking. It always fully eva…

Right, they are only approximately comparable, but the important thing to remember is that features of formalisms are never goals in themselves, but rather means to various ends. The goal is never "to have interfaces/typeclasses/traits" but to be able to specify an algorithm that works for a variety of data structures with shared properties. Moreover, I think it would be a mistake for Zig library authors to try and replicate styles used in other languages. Zig provides sufficient mechanisms for expressing programs, and it will develop its own style. There will be elements that are analogous to those in other lanugages, but not identical.

Having said that, I do support a proposal for specifying a type at the parameter declaration with some type -> bool function.

I like this quote by Leslie Lamport about comparing formalisms (he talks about specification languages rather than programming languages, but the sentiment is the same):

> Comparisons between radically different formalisms tend to cause a great deal of confusion. Proponents of formalism A often claim that formalism B is inadequate because concepts that are fundamental to specifications written with A cannot be expressed with B. Such arguments are misleading. The purpose of a formalism is not to express specifications written in another formalism, but to specify some aspects of some class of computer systems. Specifications of the same system written with two different formalisms are likely to be formally incomparable… Arguments that compare formalisms directly, without considering how those formalisms are used to specify actual systems, are useless.

Re: Interview with Zig language creator Andrew Kelley [video]

#195

Post by pron » Sun, Aug 30, 2020, 12:19 AM UTC

elcritch wrote: post #191

pron wrote: post #183

Earlier quoted context omitted.

The goal isn't to have macros but to be able to do what macros are used for. Zig has found a different and simpler way to do what macros do. comptime gives you generic types, typeclasses/concepts, typesafe printf, conditional compilation and much more, all without macros and with a simpler construct than macros.

After reading your previous comment, I read a bit more about comptime. It does seem to be able to handle most of the cases I could think of wanting macros for, and it is a nice UX in that it's really like "bounded macros" and prevents building arbitrary new semantics. Though thinking on two levels in a given function does seem tricky to me, but perhaps that's just familiarity. Personally, I kind of like having separa…

The beauty of comptime is that, unlike with macros, you don't need to think on two levels. The semantics is the same as if everything were done at runtime. To read a comptime function you can completely ignore the distinction between compilation time and runtime. To write it you need to know that some operations are only available at compile-time.

See my comment here about "Zig' ": https://news.ycombinator.com/item?id=24293611

Perhaps now you see what I meant when I said that Zig's simplicity hides its radical design.

Re: Interview with Zig language creator Andrew Kelley [video]

#196

Post by nulltype » Mon, Aug 31, 2020, 6:49 AM UTC

littlestymaar wrote: post #179

PaulDavisThe1st wrote: post #108

Earlier quoted context omitted.

Clearly you meant zig++

(This was a reference to the Go language, which after a decade saying “generics aren't needed” and even “the lack of generics is a feature”, are eventually shoehorning them in the language in their Go2 campaign.)

I think they've been saying "We haven't yet found a design that gives value proportionate to the complexity, although we continue to think about it." since 2013: https://web.archive.org/web/20130410000959/https://golang.or...

Re: Interview with Zig language creator Andrew Kelley [video]

#197

Post by LakeByTheWoods » Mon, Aug 31, 2020, 9:30 AM UTC

HourglassFR wrote: post #175

gautamcgoel wrote: post #157

Earlier quoted context omitted.

Can you elaborate a bit more about what your found lacking in Zig strings?

Well there are no strings, only byte arrays. Now that's fine if you only pass bytes around in a stream, but if wan't to do any computation it you have to assume an encoding and basically anything outside of straight ASCII will be a pain. Now you may argue that this can be handled nicely in the standard library without changing the language. This is correct, but there will be some frictions with string litterals.

What frictions do you anticipate? String literals in zig are utf8 encoded.

Re: Interview with Zig language creator Andrew Kelley [video]

#198

Post by mwkaufma » Wed, Sep 02, 2020, 4:27 PM UTC

tlb wrote: post #162

mwkaufma wrote: post #141

Earlier quoted context omitted.

Many core modern C++ types don't permit customizing the allocator. E.g. std::function

However, most std::functions have a small built-in buffer for captured variables, like 4 pointers worth. If you limit yourself to only capturing that many, there's no allocation.

I'm not saying that the default allocation strategy isn't good (in the general case), just that it's not customizable (for special needs).

Re: Interview with Zig language creator Andrew Kelley [video]

#199

Post by int_19h » Wed, Sep 02, 2020, 11:04 PM UTC

cycloptic wrote: post #148

mwkaufma wrote: post #142

Earlier quoted context omitted.

Furthermore, C++ dependencies commonly instantiate types like std::vector with the default allocator internally, rather than exposing it to the host application.

Thank you for the examples. I'm not sure std::function is a good comparison. After some research it seems this used to be in the spec, but it was removed because nobody supported it correctly and it seems it was too difficult to do it in a type-safe manner anyway: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p030... The other thing is that Zig doesn't seem to have any real plans to support C++-style closur…

C++-style closures are unrelated to custom allocators, since they're not heap-allocated.

Re: Interview with Zig language creator Andrew Kelley [video]

#200

Post by int_19h » Wed, Sep 02, 2020, 11:14 PM UTC

edflsafoiewq wrote: post #153

pron wrote: post #152

Earlier quoted context omitted.

RAII is not a question. Zig prefers explicitness, i.e. by looking at a subroutine you know exactly which code is called, its approach to releasing resource uses defer.

The question is how to do automatic resource management. There are no checks of any sort, runtime or not, to help you here (correct me if I'm wrong). RAII is not precluded by explicitness, you could require all values that require cleanup to be syntactically marked in some way and it would still be RAII. defer also cannot handle resources whose lifetimes do not correspond to nested scopes (eg. the elements of an Arra…

> defer also cannot handle resources whose lifetimes do not correspond to nested scopes

It can, it's just more explicit about it. In a language with destructors, you'd do RAII here by having a list destructor that cleans up each element in turn. In a language with defer, the same destructor becomes a regular function that you'd invoke in the deferred expression.