bkosm/kpipe

A kotlin-native library introducing a functional-style pipe.

kpipe

Pipe functions that allow for a more functional style of programming. They support chains of transformation up to 11 in size, providing excellent DX on top.

The library includes:

• pipe - a function that pipes the result of one function to the next as a parameter
• kpipe- a function that pipes the result of one function to the next as context receiver and the initial value as a parameter

The functions are implemented as a invoke override on the companion, so you can name them whatever you want with typealiases.

a little preview

kpipe/src/test/kotlin/com/bkosm/kpipe/examples/PipeExample.kt

Lines 13 to 90 in 5af8eff

	class PipeExample {
	fun interface ValueFactory<PRIMITIVE : Any, TARGET : Any> {
	fun of(value: PRIMITIVE): TARGET
	}
	@JvmInline
	value class EID private constructor(private val value: String) {
	companion object : ValueFactory<String, EID> {
	override fun of(value: String) = pipe(
	value,
	{ it.isNotEmpty() && it.isNotBlank() },
	::require,
	{ EID(value) }
	)
	}
	}
	sealed interface Event {
	val id: EID
	data class Initialized(override val id: EID, val timestamp: String) : Event
	}
	interface EventStore {
	fun get(id: EID): Event?
	fun store(event: Event): Result<Unit>
	}
	fun InMemoryEventStore() = object : EventStore {
	private val storage = mutableMapOf<EID, Event>()
	override fun get(id: EID) = pipe(
	id,
	storage::get
	)
	override fun store(event: Event) = pipe(
	event,
	{ storage[it.id] = it },
	Result.Companion::success
	)
	}
	@Test
	fun `you can't create a blank EID`() {
	pipe(
	runCatching { EID.of("") }.exceptionOrNull(),
	{ assertIs<IllegalArgumentException>(it) } // kotlin does not allow method reference with generics
	)
	}
	@Test
	fun `can store and retrieve events`() {
	// given
	val uut = InMemoryEventStore()
	val id = EID.of("1")
	val event = Event.Initialized(id, "2077-03-03T10:15:30Z")
	// when/then
	pipe(
	id,
	uut::get,
	::assertNull,
	)
	kpipe(
	event,
	{ uut.store(this) },
	{ isSuccess },
	{ assertTrue("Failed for event $it") { this } },
	)
	pipe(
	id,
	uut::get,
	{ expect(event) { it } }
	)
	}
	}

currently available via JitPack

repositories {
    // all the other ones that you might need...

    maven { url = uri("https://jitpack.io") }
}

// and then

dependencies {
    // all the other ones that you might need...
    
    testImplementation("com.github.bkosm:kpipe:1.0.0")
}

you decide on the features!

Drop an issue with what functionality you could use in your Kotlin tuple or submit a PR!