risc-v开发基础 Scala 偏函数与Function1的实验---(26)

joe

val too:Function1[Int,Int] = {
  case x =>x + x + x
}
println(too)  //其实是Function1这个trait的toString 源码：override def toString() = "<function1>"
println(too(3)) //9
def fun(i:Int):Int = {
  i+i+i
}
println(fun(3)) //9
def too2:Function1[Int,Int] = {
  case x => x + x + x
}
println(too2) //<function1>
println(too2(3)) //9
//    val pf: PartialFunction[Int,Int] = too2.asInstanceOf[PartialFunction[Int,Int]] //java.lang.ClassCastException: com.joe.stu.PartialFunctionTest$$anonfun$too2$1$1 cannot be cast to scala.PartialFunction
//    println(pf(3))
//    val pf: PartialFunction[Int,Int] = fun  或too 或too2 都会提示类型转换有错误
val pxf: PartialFunction[Int,Int] = {
  case x => x + x +x
}
val pxf1:Function1[Int,Int] = pxf
println(pxf1(3)) //9

joe

def fun2(a:Int,b:Int):Function2[Int,Int,Int] = (a,b)=>{
  a+b+10
}
println(fun2(1,2)) //<function2>
println(fun2(1,2)(2,3)) //15

joe

def fun3:Function2[Int,Int,Int] = (a,b)=> a+b +11
println(fun3(2,3)) //16