Embedding Stak Scheme in Rust

@raviqqe

January 14, 2024

Contents

• Embedding Scheme in Rust
• Related crates
• Release process
• Future work

Embedding Scheme in Rust

• Stak Scheme can be embeddable into Rust codes.
• Rust codes can simply "import" codes written in Stak Scheme.
• Currently, they can talk to each other only by I/O.
  • Object interoperability (maybe) in the future (probably!)

Examples

use stak_device::FixedBufferDevice;
use stak_macro::compile_r7rs;
use stak_primitive::SmallPrimitiveSet;
use stak_vm::Vm;

const HEAP_SIZE: usize = 1 << 16;
const BUFFER_SIZE: usize = 1 << 10;

let mut heap = [Default::default(); HEAP_SIZE];
let device = FixedBufferDevice::<BUFFER_SIZE, 0>::new(&[]);
let mut vm = Vm::new(&mut heap, SmallPrimitiveSet::new(device)).unwrap();

const PROGRAM: &[u8] = compile_r7rs!(r#"
    (import (scheme write))

    (display "Hello, world!")
"#);

vm.initialize(PROGRAM.iter().copied()).unwrap();
vm.run().unwrap();

assert_eq!(vm.primitive_set().device().output(), b"Hello, world!");

Examples

Macros

• compile_r7rs! compiles R7RS Scheme codes into bytecodes.
• include_r7rs! includes and compiles R7RS Scheme codes from a file path.
• They run at a compile time.

Related crates

• A stak-macro crate contains compile_r7rs! and include_r7rs!.
• A stak-compiler crate contains a compile_r7rs function which runs compiler bytecodes and a VM for it to compile another Scheme program.
  • The crate is not dependent on another Scheme interpreter.

Release process

• A (binary) bytecode file is bundled with a crate of stak-compiler on release.
  • On development, they are built by build.rs.
  • On cargo publish of the crate, the bytecode file is bundled as an asset.
• cargo install stak or the other crates do not require another Scheme interpreter anymore!

Future work

• Scheme embedded in Rust
  • Scheme/Rust object interoperability
    • VTable?
    • Serde?
• Library system
• eval procedure

Summary

• Embedding Scheme in Rust is fun!