traits - Scala: Example use for early definition / early initializer / pre-initialized fields -


scala allows make definitions so:

trait {   val v: int }  class b extends { val v = 4 }

what example use of feature?

whenever value used trait initialization. eaxmple trait:

trait usefultrait {   val parameter : int   private val myhelperobject = new myexpensiveclass(parameter) }

the parameter used substitute constructor parameter. parameter should rather made abstract method, because leaves more free space implementer.


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