如何從Future.foreach回調scala中的尾部遞歸？

Question

考慮一個Scala代碼：

def myRecursiveFunction(id:string):Unit= { 
    myAsyncDao.search(id).foreach {response=> 
     myRecursiveFunction(response.id) 
    } 
} 
//myAsyncDao.search returns a Future 
//response have id field for further computations 

如果我把@tailrec頂部運算函數，編譯抱怨Recusive call not in tail position。

它可以被優化爲尾遞歸嗎？

Answer 1

如何

def myRecursiveFunction(id:string):Future[Unit]= { 
    myAsyncDao.search(id) flatMap {response=> 
     myRecursiveFunction(response.id) 
    } 
} 

更新：

def search(id: Future[Int]) = Future { 5 } 

@tailrec 
def myRecursiveFunction(id: Future[Int]):Future[Unit]= { 
    val response = search(id) 
    myRecursiveFunction(response)  
}