Scala で open class

暗默の型變換 (inplicit conversion) で簡單

code:scala

class A {}

implicit class AWithB(a: A) {

def b: A = {

processSomething()

a

}

}

new A().b

冗長には

code:scala

import scala.language.implicitConversions

class A {}

implicit def aAsAWithB(a: A): AWithB = new AWithB(a)

class AWithB(a: A) {

def b: A = {

processSomething()

a

}

}

new A().b