Scala 14：错误：设备不带参数

Question

New to scala world and for exercise , executed below lines of code in windows REPL. getting error Unit does not take parameters.Any idea on this.

scala> :paste
// Entering paste mode (ctrl-D to finish)

val x:Int = 10
println(x)
{
val x:Int =20
println(x)
}
println(x)

// Exiting paste mode, now interpreting.

<pastie>:14: error: Unit does not take parameters
{
^

scala>

Answer 1

That is because scala thinks println() is taking another parameter when it sees {} . You simply can test with following code as well,

scala> println(8){}
                 ^
       error: Unit does not take parameters

scala> println(1)()
                 ^
       error: Unit does not take parameters

You need to put a new line between println() and {} to make compiler happy.

example: https://scastie.scala-lang.org/prayagupd/jbPWBesyTvihwue8soE5Og

scala> :paste
// Entering paste mode (ctrl-D to finish)

val x:Int = 10
println(x)

{
val x:Int =20
println(x)
}
println(x)

// Exiting paste mode, now interpreting.

10
20
10
x: Int = 10