我刚刚开始Scala，并且正在修改工作表。例如：
I've just started Scala and am tinkering in worksheets. For example:
def merp(str: String) : String = s"Merrrrrrrp $str" val merp2 = (str: String) => s"Merrrrrrrp $str" val merp3 = (str: String) => merp(str) val merp4 = merp _ merp("rjkghleghe") merp4("rjkghleghe")以及相应的工作表结果：
And the corresponding worksheet results:
merp: merp[](val str: String) => String merp2: String => String = <function1> merp3: String => String = <function1> merp4: String => String = <function1> res0: String = Merrrrrrrp rjkghleghe res1: String = Merrrrrrrp rjkghleghe，例如， val merp5 = merp 会产生一个错误，因为显然方法不能以函数的方式作为值。但我仍然可以将方法作为参数传递。我在下面的代码片段中演示了这一点，它改编自类似的SO问题： $ b
Saying, for example, val merp5 = merp produces an error, because apparently methods cannot be values the way functions can. But I can still pass methods as arguments. I demonstrate this in the following code snippet, adapted from a similar SO question:
def intCombiner(a: Int, b: Int) : String = s"herrrrrrp $a derrrrrrp $b" def etaAbstractor[A, B](combineFoo: (A, B) ⇒ String, a: A, b: B) = combineFoo(a, b) etaAbstractor(intCombiner, 15, 16)工作表结果：
worksheet result:
intCombiner: intCombiner[](val a: Int,val b: Int) => String etaAbstractor: etaAbstractor[A,B](val combineFoo: (A, B) => String,val a: A,val b: B) => String res10: String = herrrrrrp 15 derrrrrrp 16
欢迎理论，计算机科学的答案，以及指向语言规范。谢谢！
Theoretical, computer sciencey answers are welcome, as are pointers to any relevant points in the language specification. Thanks!
推荐答案免责声明：我不是计算机科学家，但我会尝试猜测：
Disclaimer: I'm not a computer scientist, but I will try to guess:
方法是对象的一部分，不存在于其外部。你不能单独传递方法。 Closure是封装状态的另一种（等价的）方式，通过将对象方法转换为独立函数（这是另一个在Scala中使用 apply（）方法的对象） ）你正在创建一个闭包。这个过程被称为eta-expansion。 §3.3.1， §6.26.5
Method is a part of an object and doesn't exist outside of it. You can't pass method alone. Closure is another (equivalent?) way of encapsulating state, by converting an object method to a standalone function (which is by the way just another object with apply() method in Scala) you are creating a closure. This process is known as eta-expansion. §3.3.1, §6.26.5
您不必这样做。您也可以编写 val merp3：（String => String）= merp 。 §6.26.5
You don't have to. You can also write val merp3 : (String => String) = merp. §6.26.5
是的， merp4 也是eta-expansion。 §6.7
Yes, merp4 is eta-expansion too. §6.7
§6.26.2
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