Scala 2.10中的__FUNC__宏

Question

在Scala 2.9.x中，我编写了func函数，它返回了执行func（）函数的名称，就像 FUNC C预处理器宏一样。据我所知，在Scala2.10中，我应该能够写一些比抛出异常更优雅的东西。

我该怎么办？在此先感谢您的帮助。

object TestMyLog extends App {
    val MatchFunc = """(.+)\(.+""".r

def func(i_level: Int): String = {
    val s_rien = "functionNotFound"
    try {
    throw new Exception()
    } catch {
    case unknwn => unknwn.getStackTrace.toList.apply(i_level).toString match {
            case MatchFunc(funcs) => funcs.split('.').toList.last
        case _ => s_rien
    }
    } finally {
    s_rien      
    }
}

def tracedFunction1 = func(1)
def tracedFunction2 = func(1)

println(tracedFunction1)
assert(tracedFunction1=="tracedFunction1")
println(tracedFunction2)
assert(tracedFunction2=="tracedFunction2")
}

Answer 1

import scala.reflect.macros.Context
import scala.language.experimental.macros

def impl(c: Context) = {
  import c.universe._
  c.enclosingMethod match {
    case DefDef(_, name, _, _, _, _) =>
      c.universe.reify(println(c.literal(name.toString).splice))
    case _ => c.abort(c.enclosingPosition, "no enclosing method")
  }
}

scala> def printEnclosingMethod = macro impl
defined term macro printEnclosingMethod: Unit

scala> def foo = printEnclosingMethod
foo: Unit

scala> foo
foo

scala> printEnclosingMethod
<console>:32: error: no enclosing method
              printEnclosingMethod
              ^

Answer 2

我不确定在没有异常的情况下执行此操作，但实际上您不需要抛出/捕获异常来获取堆栈跟踪：

(new Exception).getStackTrace.toList

Answer 3

这样你就应该为每个funName的灵魂Function，Function1等重载Function2。也许一些大师会帮忙？

// define macro
import scala.language.experimental.macros
import scala.reflect.macros.Context
object Macros {
  def funName(xs: Function0[_]) = macro funName_impl
  def funName_impl(c: Context)(xs: c.Expr[Function0[_]]) = { 
    c.literal(xs.tree.children.head.toString.split("\\.").last)
  }
}

// exec (in a next compile run)
def haha: Unit = println("Function name: " + Macros.funName(haha _))
haha