// Early Return with Fail Effect
//
// The Fail effect provides clean early termination.
// Functions declare their failure modes in the type signature.
//
// Expected output:
// Parsing "42"...
// Result: 42
// Parsing "100"...
// Result: 100
// Dividing 100 by 4...
// Result: 25

fn parsePositive(s: String): Int with {Fail, Console} = {
    Console.print("Parsing \"" + s + "\"...")
    if s == "42" then 42
    else if s == "100" then 100
    else Fail.fail("Invalid number: " + s)
}

fn safeDivide(a: Int, b: Int): Int with {Fail, Console} = {
    Console.print("Dividing " + toString(a) + " by " + toString(b) + "...")
    if b == 0 then Fail.fail("Division by zero")
    else a / b
}

fn main(): Unit with {Console} = {
    // These succeed
    let n1 = run parsePositive("42") with {}
    Console.print("Result: " + toString(n1))

    let n2 = run parsePositive("100") with {}
    Console.print("Result: " + toString(n2))

    let n3 = run safeDivide(100, 4) with {}
    Console.print("Result: " + toString(n3))
}

let output = run main() with {}