vscode-extension-samples/wasm-component-model-async/wit/calculator.wit

// wit/calculator.wit
package vscode:example;

interface types {
	record operands {
		left: u32,
		right: u32
	}

	variant operation {
		add(operands),
		sub(operands),
		mul(operands),
		div(operands)
	}
}
world calculator {
	use types.{ operation };
	import log: func(msg: string);

	export calc: func(o: operation) -> u32;
}