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Comment by WhereIsTheTruth | Hacker News Reader

Could be a fun python alternative

Questions:

- value/object semantic: i peeked at some code, and i can't tell what is a value, and what is a reference type, is everything heap allocated?

- tooling: what's the state of their language server? does it work with all of their language features?

- debugging: does gdb/lldb understand nim's types and slices?

And finally: is a no-gc mode available?

I'll play with it later today, it's always been in my todo list of languages to try, now is the perfect time

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Reference semantics are part of the type.

So "var i: int" is value, "var i: ref int" is a heap allocated reference that's deterministically managed like a borrow checked smart pointer, eliding reference counting if possible.

You can turn off GC or use a different GC, but some of the stdlib uses them, so you'd need to avoid those or write/use alternatives.

Let me say though, the GC is realtime capable and not stop the world. It's not like Java, it's not far off Rust without the hassle.

1. Nim uses 'var' modifier to pass by reference, e.g. "proc (n: var int)...", default behaviour is pass by value. And there're also raw pointers and references (safe pointers).

>is a no-gc mode available?

You can disable gc, but most of standard library depends on it. But in Nim 2.0 there's finally support for ARC and ORC (ARC + cycle collector).

> default behaviour is pass by value

Is not exactly true, smaller than 24 bytes is passed by value, the compiler optimizes larger calls and passes by reference implicitly.

I've been searching and can't find it: A in ARC is for automatic, what does the O stand for?

O is a visual pun because it adds a cycle collector to ARC.

I assumed the O was for "optimised", but apparently it stands for "cycle":

https://nim-lang.org/blog/2020/12/08/introducing-orc.html

> i can't tell what is a value

If a type is declared with 'ref', it's a reference type. Otherwise, it's a value type.

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