Sertyp - Rust Backend

Rust data structures for Typst values with serialization and deserialization from and into the sertyp CBOR format. Allows for straighforward communication between typst and WASM plugins.

Overview

This library provides serialization and deserialization logic for the sertyp CBOR format into a handy rust data-structure and utility functions.

Supported Types

Primitives: bool, int, float, string, bytes, none, auto

Common: array, dict, function, type, decimal

Typst-specific: alignment, angle, color, length, relative, ratio, fraction, duration, datetime, symbol, label, regex, stroke, gradient, tiling, direction, version, module, styles, content

Writing a sertyp powered Rust WASM plugin

use wasm_minimal_protocol::*;
use sertyp::*;

#[cfg(target_arch = "wasm32")]
initiate_protocol!();

#[wasm_func]
pub fn fibonacci(
    data: &[u8],
) -> Vec<u8> {
    let n: i32 = match deserialize_cbor(data) {
        Ok(Item::Integer(i)) => {
            match i.try_into() {
                Ok(n) => n,
                Err(_) => error!("Invalid integer range")
            }
        },
        Ok(other) => {
            error!("Expected integer, found {}", other.type_name());
        }
        Err(e) => {
            error!("Deserialization Error: {}", &e);
        }
    };
    
    let (mut v0, mut v1) = (0, 1);
    for _ in 0..n {
        (v0, v1) = (v1, v0 + v1);
    }

    let result: Integer = v1.into();
    serialize_cbor(&result.into()).unwrap()
}

#import "@preview/sertyp:0.1.1";
#let fibonacci(n) = {
    let plugin = plugin("./target/wasm32-unknown-unknown/release/test_plugin.wasm");
    sertyp.deserialize_cbor(test_plugin.cycle(sertyp.serialize_cbor(data)));
}

#assert(fibonacci(10) == 89)

Development

Running Tests

The test suite in ../test_plugin/ validates roundtrip serialization for all types:

cd ../test_plugin
cargo build --release
# Then run via Typst
typst compile ../test_plugin/test.typ --root ..

Adding New Types

To add a new type:

1. Create src/types/<newtype>.rs with serialization logic
2. Add variant to Item enum in src/types/mod.rs
3. Update ItemTagged_ enum for CBOR encoding
4. Implement conversion in From<Item_> and From<Item> blocks
5. Add corresponding Typst module in ../typst/types/<newtype>.typ