1. You want almost all pointer parameters non null.

2. Non-null variables is very hard to fit in a language without constructors.

Approaches to avoid constructors/destructors such as ZII play very poorly with ref values as well. What you end up with is some period of time where a value is quasi valid - since non-null types need to be assigned and it's in a broken state before it's initially assigned.

It's certainly possible to create generic "type safe" non-null types in C3, but they are not baked into the language.

But having them be inside comments is just weird.

The entire rest of the language is built on pass-by-value using stack values and stack-managed hidden unique pointers. You basically never actually need to use a ref or a pointer unless you're building an interface to a C or C++ library. I having written a 40k line production application with no reference or pointer types anywhere. Almost any case you'd need is covered by simply passing a compound type or dynamic container as a mutable value, where it's impossible to perform any kind of pointer or reference semantics on it. The lifetime is already managed, so semantically it's just a value.

1. It is so big.

2. It still largely depends on GC (less important actually)

It keeps adding features, but adding features isn't what makes a language worth using. In fact, that's one of the least attractive things about C++ as well.

So my guess:

1. It betted wrong on GC trying to compete with C++.

2. After failing to get traction, kept adding features to it – which felt a bit like there was some feature that would finally be the killer feature of the language.

3. Not understanding that the added features actually made it less attractive.

4. C++ then left the GC track completely and became a more low level alternative to, at which point D ended up in a weird position: neither high level enough to feel like a high level alternative, nor low level enough to compete with C++.

5. Finally: the fact that it's been around for so long and never taking off makes it even harder for it to take off because it's seen as a has-been.

Maybe Walter Bright should create a curated version of D with only the best features. But given how long it takes to create a language and a mature stdlib, that's WAY easier said than done.

https://ziglang.org/

    case SOME_BAD_THING, SOME_OTHER_CONDITION, HERE_IS_NUMBER_THREE:
        foo();
        int y = baz();

    case SOME_BAD_THING, SOME_OTHER_CONDITION, 
      HERE_IS_NUMBER_THREE, AND_NUMBER_FOUR, AND_NUMBER_FIVE,
      AND_THE_LAST_ONE:
        foo();
        int y = baz();

    case SOME_BAD_THING:
    case SOME_OTHER_CONDITION:
    case HERE_IS_NUMBER_THREE:
    case AND_NUMBER_FOUR:
    case AND_NUMBER_FIVE:
    case AND_THE_LAST_ONE:
        foo();
        int y = baz();
  

    case SOME_BAD_THING,
    case SOME_OTHER_CONDITION,
    case HERE_IS_NUMBER_THREE,
    case AND_NUMBER_FOUR,
    case AND_NUMBER_FIVE,
    case AND_THE_LAST_ONE:
        foo();
        int y = baz();

The try-catch has nice composability:

    try {
        int x = foo_may_fail();
        int y = bar_may_fail(x);
    } catch (... ) {
        ...
    }

    int? x = foo_may_fail();
    int? y = bar_may_fail(x);
    if (catch err = y) {
       ...
       return;
    }
    // y is implicitly unwrapped to "int" here

Named parameters are already in the language.

Regarding concurrency, I don't want to pick a single concurrency model over another. I will see what hooks I can make for userland additions, but the language will not be opinionated about concurrency.

The comparison shouldn't be with C, it should be with C++, Rust, or Zig.

The place to go is actually the C3 comparison page:

https://c3-lang.org/faq/compare-languages/

There you can see that there are very few items "in C3 but not Rust", for example. Mainly "it's a familiar C-like language".

I am also suspicious of the macro system. I'd like more of an explanation of how it works. Especially how it relates to Zig comptime, and whether it has "hygiene" problems. Hygiene to me means: can a variable name in a macro expansion refer to a variable outside of the macro? (The concern is that this could be accidental.)

https://c3-lang.org/generic-programming/macros/

Rust is solving a different problem, that of safety over all else. C3 on the other hand is more akin to developer experience above all else.

If you find something that should be easier to do in C3, that's a bug.

C3 is more complex than C (because of a net increase of features), but it's miles from C++ and Rust in complexity and it compiles as fast or faster than C.

Overloading is also generally missing from today's breed of C alternatives.

There has certainly been many attempts at C alternatives: eC, Cyclone etc etc

Given the widespread undefined behavior and the ways that compilers aggressively rely on that to reorganize and optimize your code, that hasn't been the case for many many years.

Sure, if you're using dmr's compiler on a PDP-11, then C is a pretty transparent layer over assembly, which is itself a fairly thin layer over the CPU. But today, C is an ambiguous high level communication language for a highly optimizing compiler which in turn produces output consumed by deep pipeline CPUs that freely reschedule the generated instructions.

If you're not doing something for each element of a collection, you should not be using a `foreach` loop. In exchange for not exposing the implementation, you immediately know the behavior. You also don't have to worry about checking the rest of the loop body for later mutations.

C++ is fine, but it's insanely slow to compile.

I generally like C++, but I could trade anything to make it faster to compile, and most of the time, I just use a small subset of C++ that I feel okay with.

There are definitely advantages to simpler tools, you can streamline development and make people more productive quicker. Compare that scenario to C++ where you first have to agree the features you're allowing and then have to police that subset throughout on every PR.

Personally when I initially learned C++ back in 1993, with Turbo C++ 1.0 for MS-DOS, I hardly saw a reason to further use C instead C++, other than being required to do so.