Scala - Variable amount of function arguments as method parameters

Question

I am a newbie fascinated by Scala looking for a way of creating a method/function that takes a variable amount of functions as parameters.

Example with the * notation used in regular VarArgs

def someMethod(aNumber: Int, multipleFunctions: Int => Boolean*) = {
    var flag = true
    for (func <- multipleFunctions; if (!func(aNumber)) flag = false
    flag
}

I realize I could accept an array of functions, but if that works it just feels like there must be a way of doing it with var args.

I'm fairly sure you can simply wrap Int => Boolean in parentheses and that would solve the problem. — stefanobaghino
– stefanobaghino, Commented Jan 18, 2018 at 21:29
@cchantep Well that was quick, thank you very much. I'm guessing you already know but this can be also written as Function[Int, Boolean], IntelliJ seems to prefer it that way. — Daniel
– Daniel, Commented Jan 18, 2018 at 21:30
@stefanobaghino You are correct, I should probably have thought of that, thanks! — Daniel
– Daniel, Commented Jan 18, 2018 at 21:32

stefanobaghino · Accepted Answer · 2018-01-26 15:06:09Z

1

The * token is evaluated with precedence over =>, so you can simply solve your problem by wrapping the Int => Boolean type in parentheses:

def someMethod(aNumber: Int, multipleFunctions: (Int => Boolean)*)
//                                              ^     here!    ^

answered Jan 26, 2018 at 15:06

stefanobaghino

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