Comment by Shadonototra | Hacker News Reader

Comment by Shadonototra | Hacker News Reader

Parent Full thread

Zig is still new, so it has room to improve

While i like Zig, it has many ergonomics issues that i just can't deal with.. and it has the tendency to make your code unnecessary verbose

- no operator overloading for your math type, you end up chaining methods..

- no function overloading, you have to do things like 'add(comptime T: type, x: antype, y: anytype)`

then: add(f32, myX, myY);

then be prepared with a shit ton of @floatCast(), it can't guess what type you use so you forced to be doubly explicit..

you end up with code that is barely readable

- unused as error, this one hurts a lot.. you can say goodbye to fast iteration time, if you make a game it'll be painful

Zig is still great, i plan to use it for some project, knowing how to use more language helps train your skills and understand pros/cons of features better

You can crosscompile with D too

    ldc2 -mtriple=x86_64-windows-msvc -c foo.d

Metaprogramming is great, you get more power with D, mixin, proper templates, type introspection

You can link without the runtime if size is a concern, i haven't had any issues with it

While D is great, it also has some issues

- float default is NaN, why... just WHY!!!!!

- char default is 0xFF....

when you expect things to be just 0, it is a pain to deal with and to remember...

Also the standard library, while useful, i wish it would make use of allocators

They have ``std.experimental.allocator`` packages, for some reason it still is experimental..

There is no tagged union.. you have to import a package for it ``std.sumtype``.. wich is bad when all other languages have built in support for that

Walter if you read this, please! union are useful, but lack of tagged union mean potential bugs in your union when you pick the wrong value...

Proposal for you:

  enum MyTag { A, B, C}

  union MyTaggedUnion: MyTag
  {
      DataA A,
      DataB B,
      DataC C
  }

  struct DataA{}
  struct DataB{}
  struct DataC{}

  auto tgu = MyTaggedUnion.B;
  switch (tgu)
  {
   case A:
   tgu. /* implicit DataA */
   break;
   // need to implement every tags, or error
  }

> float default is NaN, why... just WHY!!!!!

> char default is 0xFF....

Invalid values, perhaps? Other than making initialization mandatory, this seems like a reasonable way of catching them. For integer types it's not really possible because all their values are valid.

I grew to agree, but that doesn't mean that's not annoying.. i'm nitpicking

> float default is NaN, why... just WHY!!!!!

All operations that are fed NaN as an operand produce a NaN result. This makes it very obvious when the initialization of a float has been neglected. Defaulting to 0.0 means uninitialization bugs are nearly impossible to detect.

> char default is 0xFF....

Same thing. It's intended to flush out uninitialization bugs.

Why is your proposal better than this:

  import std.sumtype;
  
  void main(){
   struct A { int a; }
   struct B { string b; }
   struct C { bool c; }
   
   alias TaggedUnion = SumType!(A, B, C);
   
   auto tgu = TaggedUnion(B("hi"));
   int i = tgu.match!(
    (A a) => a.a,
    (B b) => b.b.length,
    (C c) => c.c * 5
   );
   assert(i == 2);
  }

If you miss out a `match` handler for any of A, B, C you get a compile-time error. Or you can use a generic handler which will be instantiated for any type not explicitly handled. https://dlang.org/phobos/std_sumtype.html

I'd take a language that have built in support for tagged union over having to import a module and rely on templates

I know of sumtype, and i think it is a mistake for D to rely on this for such important language feature

I'm not a language dev, so i can't do much to help, using switch/union/enum is more natural, is cleaner, and is easier to add support for IDEs, everyone on the same page

That's in areas like this where the language falls short, and i can see people instead choosing alternatives

https://github.com/dlang/phobos/blob/master/std/sumtype.d

a mess of templates and imports to std.traits

using this will make your compile speed tank.. another reason to avoid

it's very sad that people recommend this instead of asking for built-in version, makes me sometimes reconsider my choice to use the language

if they expect language improvements to be templates, what atrocity will be added next?

this is on the same level as std::bool from C++

https://forum.dlang.org/post/bkgvdewkjwthmlfemnjm@forum.dlan...

> The good news is, I have not put a lot of effort so far into micro-optimizing the compile-time performance of match, so there is almost certainly room for improvement.

it is shame that it ended up in the standard library

once Walter will be gone, i will have no faith in the language anymore

bool is a built-in type in C++...

Reply on news.ycombinator.com