One year of Roto, a compiled scripting language for Rust

A big problem I encountered in using Lua in Rust for my game engine was that I wasn't able to serde the Lua runtime such that I can snapshot a game session and save it in a file, and retrieve it in another context.

[0]: https://codeberg.org/NLnetLabs/roto/pulls/358

When you made Roto what kind of workloads were you optimizing for? How are you guys benchmarking performance?

I ran a quick benchmark based on my recent work (Used AI for the code here): ``` fn sum_scalar(n: u64) -> u64 { let total = 0; let i = 0; while i

  fn sum_list(xs: List[u64]) -> u64 {
      let total = 0;
      for x in xs { total = total + x; }
      total
  }

Rust benchmark.rs ```

  use std::time::Instant;
  use roto::{List, Runtime};

  fn main() {
      let rt = Runtime::new();
      let mut pkg = rt.compile("bench.roto").unwrap();
      let sum_list   = pkg.get_function::) -> u64>("sum_list").unwrap();

      let n = 1024;
      let iters = 50_000;
      let xs: List = (0..n).collect();

      let t = Instant::now();
      for _ in 0..iters { sum_scalar.call(n); }          // adds 0..n with a counter
      let scalar = t.elapsed();

      let t = Instant::now();
      for _ in 0..iters { sum_list.call(xs.clone()); }   // adds the SAME 0..n from a List
      let list = t.elapsed();

      println!("sum_scalar (counter):   {scalar:?}");
      println!("sum_list   (List[u64]): {list:?}");
      println!("-> {:.0}x slower", list.as_secs_f64() / scalar.as_secs_f64());
  }

  Output:
  sum_scalar (counter):   28.56ms
  sum_list   (List[u64]): 590.48ms
  -> 21x slower

The syntax is of course very Rusty, which is cool. However, a sort of obvious question comes to mind - what is the benefit of this over just writing rust, then? Just because the compile times are shorter?

EDIT: should mention I understand why embedded scripting languages exist, having embedded Lua many times. And I love a lot of these features, but to me having an embedded scripting language should simplify the language/API surface area instead of mirroring it almost 1:1. That's what I'm a bit undersold on.