What this meas in scala?

Question

I am new to scala, today I saw a function definition I could not understand:

def f(x: Int): Int = x
val func = (x: Int, y: Int, z: Int) => f(x)

So in Scala, what is the syntax of defining func ? To me, func is just a function accepts three parameters: func: (Int, Int, Int) => Int = <function3> . Why not just define func as

def func(x: Int, y: Int, z: Int): Int = f(x)

Is this for the reason of efficiency ? Since we just need to evaluate a val once.

http://stackoverflow.com/questions/18887264/what-is-the-difference-between-def-and-val-to-define-a-function See the last paragraph of the accepted response. — vptheron, Sep 03 '14 at 14:35

score -1 · Answer 1 · answered Sep 03 '14 at 14:38

func is defined as a value that holds a function with that signature, and it is initialized with such a function. At some time in the future, in a class method, you could provide a different function. It would be invoked as func(1,2,3) and return the result based on the function that was actually assigned to func at that point in time.

This provides an alternative to overriding a method in a subclass. For instance, you might have a state machine implementation that needed to respond to inputs in a different fashion, depending upon the state; this would be feasible way to respond appropriately by changing the value of the receiving function.

`func` is a `val`. You can't re-assign it. – The Archetypal Paul Sep 03 '14 at 15:08 — The Archetypal Paul, Sep 03 '14 at 15:08
I can only plead premature senility. You are correct. – Bob Dalgleish Sep 03 '14 at 18:51 — Bob Dalgleish, Sep 03 '14 at 18:51

What this meas in scala?

1 Answers1