kotlin - Kotlin 是否支持一元理解？

Question

像 C# 中的 LINQ，Scala 中的理解，Kotlin 中的类似内容？如果不支持，是否有计划？

Answer 1

没有特殊的关键字(do/for)，因此没有像其他语言那样直接翻译成嵌套的 flatMap(去糖)。

但是单子(monad)理解可以通过协程来实现。

来自 Arrow 文档:https://arrow-kt.io/docs/patterns/monad_comprehensions/#comprehensions-over-coroutines

Comprehensions over coroutines

This feature is known with multiple names: async/await, coroutines, do notation, for comprehensions…each version contains certain unique points but all derive from the same principles. In Kotlin, coroutines (introduced in version 1.1 of the language) make the compiler capable of rewriting seemingly synchronous code into asynchronous sequences. Arrow uses this capability of the compiler to bring you coroutines-like notation to all instances of the Monad typeclass.

This means that comprehensions are available for Option, Try, List, Reader, Observable, Flux or IO all the same.

对于协程，另请参阅“Deep into Coroutines on JVM @ KotlinConf 2017”:https://www.slideshare.net/elizarov/deep-dive-into-coroutines-on-jvm-kotlinconf-2017?next_slideshow=1