antonyharfield

// Result is a superpowered enum that can be Success or Failure
// and the basis for a railway junction
sealed class Result<T>
data class Success<T>(val value: T): Result<T>()
data class Failure<T>(val errorMessage: String): Result<T>()

// Composition: apply a function f to Success results
infix fun <T,U> Result<T>.then(f: (T) -> Result<U>) = 
    when (this) {
        is Success -> f(this.value)