Understanding what 'type' keyword does in Scala

Question

I am new to Scala and I could not really find a lot about the type keyword. I am trying to understand what the following expression may mean:

ty         


        

Answer 1

Yes, the type alias FunctorType is just a shorthand for

(LocalDate, HolidayCalendar, Int, Boolean) => LocalDate

Type aliases are often used to keep the rest of the code simple: you can now write

def doSomeThing(f: FunctorType)

which will be interpreted by the compiler as

def doSomeThing(f: (LocalDate, HolidayCalendar, Int, Boolean) => LocalDate)

This helps to avoid defining many custom types that are just tuples or functions defined on other types, for example.

There are also several other interesting use cases for type, as described for example in this chapter of Programming in Scala.