This is the definition for the interface used for examples and illustrations with the contract ID of wasmcloud:example:factorial.

This is an interface for a simple service that calculates the factorial of a whole number.

NOTE that this is just an example, and we would not recommend a real-world production scenario where you use an interface and accompanying capability provider for factorial calculations.

The following is a list of implementations of the wasmcloud:example:factorial contract. Feel free to submit a PR adding your implementation if you have a community/open source version.

Calculate a factorial, handling the error case

use wasmbus_rpc::actor::prelude::Context;
use wasmcloud_interface_factorial::{Factorial, FactorialSender};

async fn factorial(ctx: &Context, n: u32) -> u64 {
    let factorial = FactorialSender::new();
    match factorial.calculate(ctx, &n).await {
        Ok(num) => num,
        // 0 is not a possible factorial so it's obvious that an error occurred
        Err(_e) => 0,
    }
}