Improve and group samples for operations on Iterables #KT-20357

libraries/stdlib/samples/test/samples/collections/iterables.kt

@@ -20,24 +20,44 @@ import samples.*
 import kotlin.coroutines.experimental.buildIterator
 import kotlin.test.*
 
+@RunWith(Enclosed::class)
 class Iterables {
 
-    @Sample
-    fun iterable() {
-        val iterable = Iterable { buildIterator { yieldAll(1..3) } }
-        val result = iterable.mapIndexed { index, i -> index + i }
-        assertPrints(result, "[1, 3, 5]")
+    class Building {
+
+        @Sample
+        fun iterable() {
+            val iterable = Iterable {
+                buildIterator {
+                    yield(42)
+                    yieldAll(1..5 step 2)
+                }
+            }
+            val result = iterable.mapIndexed { index, value -> "$index: $value" }
+            assertPrints(result, "[0: 42, 1: 1, 2: 3, 3: 5]")
+
+            // can be iterated many times
+            repeat(2) {
+                val sum = iterable.sum()
+                assertPrints(sum, "51")
+            }
+        }
+
     }
 
-    @Sample
-    fun flattenIterable() {
-        val deepList = listOf(listOf(1), listOf(2, 3), listOf(4, 5, 6))
-        assertPrints(deepList.flatten(), "[1, 2, 3, 4, 5, 6]")
-    }
+    class Operations {
+
+        @Sample
+        fun flattenIterable() {
+            val deepList = listOf(listOf(1), listOf(2, 3), listOf(4, 5, 6))
+            assertPrints(deepList.flatten(), "[1, 2, 3, 4, 5, 6]")
+        }
+
+        @Sample
+        fun unzipIterable() {
+            val list = listOf(1 to 'a', 2 to 'b', 3 to 'c')
+            assertPrints(list.unzip(), "([1, 2, 3], [a, b, c])")
+        }
 
-    @Sample
-    fun unzipIterable() {
-        val list = listOf(1 to 'a', 2 to 'b', 3 to 'c')
-        assertPrints(list.unzip(), "([1, 2, 3], [a, b, c])")
     }
 }

libraries/stdlib/src/kotlin/collections/Iterables.kt

@@ -20,7 +20,7 @@ package kotlin.collections
 /**
  * Given an [iterator] function constructs an [Iterable] instance that returns values through the [Iterator]
  * provided by that function.
- * @sample samples.collections.Iterables.iterable
+ * @sample samples.collections.Iterables.Building.iterable
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> Iterable(crossinline iterator: () -> Iterator<T>): Iterable<T> = object : Iterable<T> {
@@ -74,7 +74,7 @@ internal fun <T> Iterable<T>.convertToSetForSetOperation(): Collection<T> =
 
 /**
  * Returns a single list of all elements from all collections in the given collection.
- * @sample samples.collections.Iterables.flattenIterable
+ * @sample samples.collections.Iterables.Operations.flattenIterable
  */
 public fun <T> Iterable<Iterable<T>>.flatten(): List<T> {
     val result = ArrayList<T>()
@@ -88,7 +88,7 @@ public fun <T> Iterable<Iterable<T>>.flatten(): List<T> {
  * Returns a pair of lists, where
  * *first* list is built from the first values of each pair from this collection,
  * *second* list is built from the second values of each pair from this collection.
- * @sample samples.collections.Iterables.unzipIterable
+ * @sample samples.collections.Iterables.Operations.unzipIterable
  */
 public fun <T, R> Iterable<Pair<T, R>>.unzip(): Pair<List<T>, List<R>> {
     val expectedSize = collectionSizeOrDefault(10)

libraries/stdlib/src/kotlin/coroutines/experimental/SequenceBuilder.kt

@@ -35,6 +35,7 @@ public fun <T> buildSequence(builderAction: suspend SequenceBuilder<T>.() -> Uni
  * Builds an [Iterator] lazily yielding values one by one.
  *
  * @sample samples.collections.Sequences.Building.buildIterator
+ * @sample samples.collections.Iterables.Building.iterable
  */
 @SinceKotlin("1.1")
 public fun <T> buildIterator(builderAction: suspend SequenceBuilder<T>.() -> Unit): Iterator<T> {