Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
990 views
in Technique[技术] by (71.8m points)

scala - Chaining operations on values without naming intermediate values

Sometimes I perform a sequence of computations gradually transforming some value, like:

def complexComputation(input: String): String = {
  val first = input.reverse
  val second = first + first
  val third = second * 3
  third
}

Naming variables is sometimes cumbersome and I would like to avoid it. One pattern I am using for this is chaining the values using Option.map:

def complexComputation(input: String): String = {
  Option(input)
    .map(_.reverse)
    .map(s => s + s)
    .map(_ * 3)
    .get
}

Using Option / get however does not feel quite natural to me. Is there some other way this is commonly done?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

Actually, it will be possible with Scala 2.13. It will introduce pipe:

import scala.util.chaining._

input //"str"
 .pipe(s => s.reverse) //"rts"
 .pipe(s => s + s) //"rtsrts"
 .pipe(s => s * 3) //"rtsrtsrtsrtsrtsrts"

Version 2.13.0-M1 is already released. If you don't want to use the milestone version, maybe consider using backport?


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...