Scala For Expressions

ForExpressionExplain.scala

case class Mascot(name: String)
case class SportTeam(mascot: Mascot)
case class City(sportTeams: List[SportTeam])
case class State(cities: List[City])
case class Country(states: List[State])

def getAllMascots(country: Country): List[Mascot] = {
    for {
        states <- country.states
        cities <- states.cities
        sportTeams <- cities.sportTeams
    } yield sportTeams.mascot
    
    // country.states.flatMap { state =>
    //     state.cities.flatMap { city =>
    //         city.sportTeams.map { sportTeam =>
    //             sportTeam.mascot
    //         }
    //     }
    // }
}

val mascot = Mascot("Donald Duck")
val sportTeam = SportTeam(mascot)
val city = City(List(sportTeam))
val state = State(List(city))
var country = Country(List(state))

getAllMascots(country)