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Error Handling

Kyna provides structured exception handling using try, catch, and throw. The compiler warns you when fallible operations (such as network I/O or file parsing) are not enclosed within an error boundary.

1. Catching Exceptions (try / catch)​

Wrap potentially failing operations inside a try block. Catch bindings have type Error (code and message).

fn loadConfig(path: str): str {
    try {
        return readFile(path);
    } catch (err) {
        slogWarn("config missing", { path: path, code: err.code });
        return "{}";
    }
}

2. Throwing Errors (throw)​

Use throw with an error message string or an error object to interrupt execution and propagate the failure:

fn validateApiKey(key: str) {
    if (len(key) < 16) {
        throw "InvalidApiKey: Key length must be at least 16 characters";
    }
}

try {
    validateApiKey("short_secret");
} catch (e) {
    print("Caught validation error:", e);
}

3. Fallible Operations & Compile-Time Checks​

The Kyna compiler analyzes call graphs for fallible functions (such as fetch or file system access) and emits diagnostics if they are called without an error boundary:

# ky check will emit a diagnostic warning if fetch is unhandled:
async fn loadData() {
    try {
        const raw = await fetch("https://api.kyna.dev/status");
        print("Received payload:", raw);
    } catch (networkError) {
        print("Network request failed:", networkError);
    }
}

Next Steps​