Scala REPL:如何查找函数类型？

Question

在Scala REPL中,可以找到值类型:

    scala> val x = 1
    x: Int = 1

    scala> :t x
    Int

但是Scala REPL没有显示函数的类型信息:

    scala> def inc(x:Int) = x + 1
    inc: (x: Int)Int

scala> :t inc
<console>:9: error: missing arguments for method inc;
follow this method with `_' if you want to treat it as a partially applied function
       inc
       ^
<console>:9: error: missing arguments for method inc;
follow this method with `_' if you want to treat it as a partially applied function
          inc
          ^

如何在Scala REPL中找到函数类型？

Answer 1

根据建议将很好地工作:

:t inc _
Int => Int

为了给出更多细节,这是必要的原因是Scala保持了"方法"之间的区别,它们在JVM中具有本机支持但不是第一类,而"函数"则被视为实例FunctionX和被视为实例作为JVM的对象.使用尾随下划线将前者转换为后者.