First example of a wasm plugin with wasmer

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "wasmer-plugin"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+[workspace]
+members = [
+	"./crates/example-plugin",
+	"./crates/example-runner",
+]

crates/example-plugin/Cargo.toml

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+[package]
+name = "example-plugin"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+
+[lib]
+crate-type = ["cdylib"]

crates/example-plugin/src/lib.rs

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+#[no_mangle]
+pub fn add(one: i32, two: i32) -> i32 {
+    one + two
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}

crates/example-runner/Cargo.toml

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+[package]
+name = "example-runner"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+wasmer = "4.2.5"

crates/example-runner/src/main.rs

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+use wasmer::{imports, Instance, Module, Store, Value};
+
+static WASM: &[u8] =
+    include_bytes!("../../../target/wasm32-unknown-unknown/debug/example_plugin.wasm");
+
+fn main() {
+    let mut store = Store::default();
+    let module = Module::new(&store, WASM).expect("failed to load Wasm module");
+
+    let import_object = imports! {};
+    let instance = Instance::new(&mut store, &module, &import_object)
+        .expect("failed to instantiate Wasm module");
+    let add = instance
+        .exports
+        .get_function("add")
+        .expect("failed to bind function add");
+    let three = add
+        .call(&mut store, &[Value::I32(1), Value::I32(2)])
+        .expect("failed to execute add");
+    let three = three.first().unwrap().unwrap_i32();
+    println!("three: {}", three); // "three: 3"
+}

src/lib.rs

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+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}