Merge pull request #37 from rikhuijzer/rh/cbor

Add cbor example

Author: astrale-sharp

README.md

@@ -40,6 +40,8 @@ See the example for your language:
 
 If you have all the required dependencies, you may build all examples by running `cargo test`.
 
+If you want to pass structured data to Typst, check how it's done with the [rust example using cbor](examples/hello_rust/).
+
 ## wasi-stub
 
 The runtime used by typst do not allow the plugin to import any function (beside the ones used by the protocol). In particular, if your plugin is compiled for [WASI](https://wasi.dev/), it will not be able to be loaded by typst.

examples/hello_rust/Cargo.lock

@@ -7,6 +7,9 @@ edition = "2021"
 crate-type = ["cdylib"]
 
 [dependencies]
+# Same package and version as Typst uses.
+ciborium = "0.2.1"
+serde = "1.0"
 wasm-minimal-protocol = { path = "../../crates/macro" }
 
 

examples/hello_rust/Cargo.toml

@@ -8,4 +8,8 @@
   assert.eq(str(p.returns_ok()), "This is an `Ok`")
   // p.will_panic()  // Fails compilation
   // p.returns_err() // Fails compilation with an error message
+
+  let encoded = cbor.encode((x: 1, y: 2.0))
+  let decoded = cbor(p.complex_data(encoded))
+  assert.eq(decoded, 3.0)
 }

examples/hello_rust/hello.typ

@@ -1,5 +1,8 @@
 use wasm_minimal_protocol::*;
 
+// Only necessary when using cbor for passing arguments.
+use ciborium::{de::from_reader, ser::into_writer};
+
 initiate_protocol!();
 
 #[wasm_func]
@@ -36,3 +39,18 @@ pub fn returns_err() -> Result<Vec<u8>, String> {
 pub fn will_panic() -> Vec<u8> {
     panic!("unconditional panic")
 }
+
+#[derive(serde::Deserialize)]
+struct ComplexDataArgs {
+    x: i32,
+    y: f64,
+}
+
+#[wasm_func]
+pub fn complex_data(arg: &[u8]) -> Vec<u8> {
+    let args: ComplexDataArgs = from_reader(arg).unwrap();
+    let sum = args.x as f64 + args.y;
+    let mut out = Vec::new();
+    into_writer(&sum, &mut out).unwrap();
+    out
+}