core/kotlinx-coroutines-core/test/guide/example-channel-04.kt

/*
 * Copyright 2016-2017 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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// This file was automatically generated from coroutines-guide.md by Knit tool. Do not edit.
package kotlinx.coroutines.experimental.guide.channel04

import kotlinx.coroutines.experimental.*
import kotlinx.coroutines.experimental.channels.*

fun produceNumbers() = produce<Int> {
    var x = 1
    while (true) send(x++) // infinite stream of integers starting from 1
}

fun square(numbers: ReceiveChannel<Int>) = produce<Int> {
    for (x in numbers) send(x * x)
}

fun main(args: Array<String>) = runBlocking<Unit> {
    val numbers = produceNumbers() // produces integers from 1 and on
    val squares = square(numbers) // squares integers
    for (i in 1..5) println(squares.receive()) // print first five
    println("Done!") // we are done
    squares.cancel() // need to cancel these coroutines in a larger app
    numbers.cancel()
}