kotlin-stdlib/kotlin.sequences/SequenceScope

SequenceScope

abstract class SequenceScope<in T>(source)

The scope for yielding values of a Sequence or an Iterator, provides yield and yieldAll suspension functions.

Since Kotlin

1.3

See also

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   val sequence = sequence {
    val start = 0
    // yielding a single value
    yield(start)
    // yielding an iterable
    yieldAll(1..5 step 2)
    // yielding an infinite sequence
    yieldAll(generateSequence(8) { it * 3 })
}

println(sequence.take(7).toList()) // [0, 1, 3, 5, 8, 24, 72] 
   //sampleEnd
}
import kotlin.test.*

fun main() { 
   //sampleStart 
   fun fibonacci() = sequence {
    var terms = Pair(0, 1)

    // this sequence is infinite
    while (true) {
        yield(terms.first)
        terms = Pair(terms.second, terms.first + terms.second)
    }
}

println(fibonacci().take(10).toList()) // [0, 1, 1, 2, 3, 5, 8, 13, 21, 34] 
   //sampleEnd
}

Functions

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abstract suspend fun yield(value: T)

Yields a value to the Iterator being built and suspends until the next value is requested.

Since Kotlin 1.3
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suspend fun yieldAll(elements: Iterable<T>)

Yields a collections of values to the Iterator being built and suspends until all these values are iterated and the next one is requested.

Since Kotlin 1.3
abstract suspend fun yieldAll(iterator: Iterator<T>)

Yields all values from the iterator to the Iterator being built and suspends until all these values are iterated and the next one is requested.

Since Kotlin 1.3
suspend fun yieldAll(sequence: Sequence<T>)

Yields potentially infinite sequence of values to the Iterator being built and suspends until all these values are iterated and the next one is requested.

Since Kotlin 1.3