Swift Functional Programming - Second Edition

<*> operator

The <*> operator is used to conditionally apply the other parameters to our curried init method. The definition is as follows:

public func <*> <T, U>(f: Decoded<(T) -> U>, x: Decoded<T>) -> Decoded<U> {     return x.apply(f) } func apply<U>(_ f: Decoded<(T) -> U>) -> Decoded<U> {     switch (f, self) {     case let (.success(function), _): return self.map(function)     case let (.failure(le), .failure(re)): return .failure(le + re)     case let (.failure(f), _): return .failure(f)     } }