scala - How can I specify multiple constructors in the case class? -

i'm trying create case class multiple constructors:

object app {   def main(args: array[string]) {     val = something("abc", 100500, _ % 2 == 0)     val b = something(true, 10, 20)        println(s"$a - $b")   } }  case class something(s: string, n: int, p: int => boolean) {   /*   additional constructor -- wrong way! -- imposible invoke outside class   def this(b: boolean, x: int, y: int) {     this("", 0, (i: int) => % x + y == 0)   }   */ } 

so far code doesn't work:

error:(10, 23) type mismatch;  found   : boolean(true)  required: string     val b = something(true, 10, 20)                       ^ 

to fix need create companion object hold apply function represents new constructor something class:

object {       def apply(b: boolean, x: int, y: int) = {     new something(if (b) "" else "default", 0, _ => {       (x + y) % 2 == 0     })   }    } 

it inconvenient. maybe there other way place multiple constructors case class?

actually works, have use new auxiliary constructors not have apply generated case class:

case class something(s: string, n: int, p: int => boolean) {   def this(b: boolean, x: int, y: int) {     this("", 0, (i: int) => % x + y == 0)   } }  new something(true, 5, 5) // works 

if want something(true, 5, 5) work, need create companion object said. think because otherwise case class won't able work pattern matching now, or have been more complicated. , notice pattern matching won't work in case

also remember case class supports default constructors case class something(s: string = "default") might you, not fix example unfortunately