scala - Why this error : type mismatch; found : Unit required: String => Unit -

below code :

object gen {   println("welcome scala worksheet")    case class cs(funtorun: string => unit)    val l: list[cs] = list(      cs(open("filepath"))      )    def open(path: string): unit = {     java.awt.desktop.getdesktop.open(new java.io.file(path))   } } 

causes compiler error :

type mismatch; found : unit required: string => unit 

but open function of of type string => unit , param type of funtorun string => unit ?

cs accepts function string unit, you're passing result of open, unit.

if want pass open function instead, need do:

cs(open) 

although without knowing you're trying achieve, it's impossibile provide sensible solution.

a possible alternative performing open action @ later time

case class cs(funtorun: () => unit) // function not taking parameters longer val cs = cs(() => open("filepath")) // 'open' not performed here cs.funtorun() // 'open' performed here 

this way open function not evaluated when passed cs constructor.