Comment by hongbo_zhang

These are the usual questions I seek answers to first when seeing a new programming language:

  - What does writing asynchronous code look like
  - Will it have any novel or less mainstream features, e.g.
    - Algebraic effects [1]
    - Contexts/Capabilities [2]
    - Linear types [3]
  - Is the type system sound and does it support/need type casts
  - Does the language support interfaces/traits/protocols
  - How rich are generics, e.g.
    - Explicit variance annotations on type parameters
    - Lower or upper bound constraints on type parameters
    - Higher-kinded types
  - Is structural vs nominal subtyping more prevalent
  - Does it have algebraic data types? Generalized algebraic data types?

[1] https://v2.ocaml.org/manual/effects.html

[2] https://docs.hhvm.com/hack/contexts-and-capabilities/introdu...

[3] https://austral-lang.org/linear-types

I think people would like to know about licenses, pricing, and control over the project. Perhaps your commercial strategy doesn't benefit from divulging that information now, but secrecy and uncertainty can kill interest.

Your docs at https://moonbitlang.com/docs/syntax/ are unreadable due to the text and background colour

Is having a dedicated fn keyword necessary? I mean, what’s the fundamental difference between a func and a fn ?

* Is there a need to differentiate func and fn? * Part of the function signature is "->" to indicates what it returns. Is this arrow needed? * For new types, you use syntax "struct User". I think Go got it right in this case where types are created with "type User struct", which can also create function types for fn variables like "type AssignUser func(name: String, id: Int) -> Int". * Does it help the lexer/parser to have the ":"? In function signature, do you need the ":" in func(name: String)? Could it be "func(name String)"? Same with type declaration but not assignment "mut elems: List[Int]", could that not be "mut elems List[int]"?

I'm picking nits. Overall I like it.

Oh hey. Wasn't you the lead developer of Bucklescript/Rescript compiler? This gonna be epic.

"Moonbit makes programming easier with its automatic memory management, setting it apart from Rust."

I'm curious how it handles allocations/deallocations (seemingly) without a GC or a borrow checker?

Edit: I see you mention a GC in another comment (https://news.ycombinator.com/item?id=37186990), but the binary is really small despite that. Does Moonbit just plan to lean on Wasm's proposed built-in GC, once that's ready? And if so, I'm curious how some of the examples in the docs work right now since (I believe) that proposal hasn't been shipped anywhere yet

Nice demo, I tried some of the examples and tweaked to see what happens. I noticed no mention of UTF-8 and I tried to add some arabic letters and other RTL letters and it printed garbage chars.

Are langs other than english supported?

Glad to see new languages designed around having good support for IDEs. matklad (rust analyzer) and I wrote a bit about this:

- https://matklad.github.io/2023/08/01/on-modularity-of-lexica...

- https://azdavis.net/posts/pl-idea-tooling/

I think pure functions, sum/product types, and pattern matching are generally accepted as an excellent way to model and manipulate pure data. I wonder what the team’s thoughts are about handling less pure things like asynchrony and I/O, as well as more interesting control flow like exceptions/panicking, coroutines, generators, iterators, etc.

In the lexical closure doc example, why choose to show variable name shadowing? What is the purpose of `let x = 3` in the below?

let x = 3 func foo(x: Int) { fn inc() { x + 1 } // OK, will return x + 1 fn fail() { y + 1 } // fail: The value identifier y is unbound. }

`foo` also captures the global `x`, but shadows it with the parameter `x`.

Can `Generics` be generic - are there higher kinds? Are they all invariant, or do they have variance and if so what is the notation?

Maybe I missed it - can methods be destructured from structs? Can enums have methods?

Is there partial application for methods and functions?

The docs don't seem to cover how you're supposed to interact with the host environment from within Moonbit. How do you define imported and exported functions?

I loaded the IDE but don't see examples of doing graphics or UI. The docs are also silent on this topic, as far as I can tell.

Is graphics or UI programming possible in MoonBit?

I couldn't see any reference to default parameters. Are they a thing?

I would quite like the ability to have something like

func makeBox(width: Int = 100, height: Int = width) -> BoxThing

everything else I've seen, I like the look of. One of my litmus tests for languages is to have the ability to make decent Vector types, tuples and operator overloading should perform that function nicely.

Very cool, I really love to see these new wasm native languages, very exciting.

Do you have any plans for a standard library? Build one specific for the language, or will perhaps try use or create/collaborate on a cross language standard library based on wasm component model? Is this even possible or good idea?

May I ask the toolchain you're using to build Moonbit?

Is there anything for binding Moonbit code to JavaScript, like Emscripten's Embind?

https://emscripten.org/docs/porting/connecting_cpp_and_javas...

What do you think of that approach?

Will things change as WebAssembly evolves?

Why not go for global type inference? Should be possible with the relatively simple type system

Will the compiler be open sourced?