Lambdas: Dot shorthand

● Beginner3 min

In an argument, .something is short for a lambda over one value: .upper() means x => x.upper().

type Order {
    amount: Int
    paid: Bool
}

fn main() {
    const names = ["asha", "ravi", "meenakshi"]
    print(names.map(.upper()))
    print(names.filter(.len() > 4))
    const orders = [Order(amount: 300, paid: true), Order(amount: 120, paid: false)]
    print(orders.filter(.paid).sum(.amount))
}

kavach run dot.kav

["ASHA", "RAVI", "MEENAKSHI"]["meenakshi"]300

.paid reads the paid field of each order, and .len() > 4 asks of each name whether it is longer than 4. No parameter to name, nothing to misread.