gmk57

inline fun <R, T> Result<T>.flatMap(transform: (T) -> Result<R>): Result<R> =
    fold({ transform(it) }, { Result.failure(it) })

fun main() {
    getUserInput()
        .flatMap { input -> parseInput(input) }
        .flatMap { numbers -> calculateMax(numbers) }
        .onSuccess { maxNumber -> println("max: $maxNumber") }
        .onFailure { throwable -> throwable.printStackTrace() }
}

gmk57

/**
 * Coroutine-based solution for delayed and periodic work. May fire once (if [interval] omitted)
 * or periodically ([startDelay] defaults to [interval] in this case), replacing both
 * `Observable.timer()` & `Observable.interval()` from RxJava.
 *
 * In contrast to RxJava, intervals are calculated since previous run completion; this is more
 * convenient for potentially long work (prevents overlapping) and does not suffer from queueing
 * multiple invocations in Doze mode on Android.
 *
 * Dispatcher is inherited from scope, may be overridden via [context] parameter.

gmk57

/**
 * Starts collecting a flow when the lifecycle is started, and **cancels** the collection on stop.
 * This is different from `lifecycleScope.launchWhenStarted { flow.collect{...} }`, in which case
 * the coroutine is just suspended on stop.
 */
inline fun <reified T> Flow<T>.collectWhileStarted(
    lifecycleOwner: LifecycleOwner,
    noinline action: suspend (T) -> Unit
) {
    object : DefaultLifecycleObserver {

gmk57

private const val TAG = "MainActivity"

class MainActivity : AppCompatActivity(R.layout.activity_main) {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        getString(R.string.str10).let {
            Log.i(TAG, "str '${it.replace("\n", "\\n")}', raw '$it'")
            findViewById<TextView>(R.id.text).apply {
                text = it

gmk57

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.appcompat.app.AppCompatActivity
import androidx.fragment.app.DialogFragment
import androidx.fragment.app.Fragment
import androidx.lifecycle.DefaultLifecycleObserver
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleOwner
import androidx.viewbinding.ViewBinding

gmk57

/**
 * Analogue of [runCatching] with retry, delay & logging added.
 * Re-throws CancellationException to avoid the need to explicitly skip it in [onFailure].
 * Intervals are calculated since previous failure.
 */
@ExperimentalTime
suspend fun <T> runRetrying(
    times: Int,
    interval: Duration,
    name: String,