scala - 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() 的函数的名称，就像FUNC C 预处理器宏一样。我知道在 Scala2.10 中我应该能够写出比抛出异常更优雅的东西来完成这项工作。

我该怎么做？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

我不确定是否要在没有异常的情况下执行此操作，但您实际上并不需要抛出/捕获异常来获取堆栈跟踪：

(new Exception).getStackTrace.toList

Answer 3

这样，您应该funName为每个Functionarities: Function1,Function2等重载。也许某些大师会有所帮助？

// 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