stackless scala with free monad例val Zero = BigInt(0) val One = BigInt(1) lazy val factorial: BigInt => BigInt = { case Zero | One => One case n => n * factorial(n - 1) } scala> factorial(10000) java.lang.StackOverflowError at scala.math.BigInt$.maxCached(BigInt.scala:22) at scala.math.BigInt$.apply(BigInt.scala:39) at scala.math.BigInt$.int2bigInt(BigInt.scala:102) at $anonfun$factorial$1.apply(<console>:17) at $anonfun$factori
