Inheritance and initialization in Scala -

i have 2 scala classes (paraphrased):

abstract class genericparser[t] {   val linefilter : string => boolean    parsedata()    def parsedata() : t {     for( line <- .... if linefilter(line) )       // things   } }  class salesparser extends genericparser[salesrow] {   val linefilter = line => !line.startswith("//")    // .... } 

the problem linefilter null in parsedata, presumably because parsedata called while primary genericparser constructor still running, subclass hasn't initialized members.

i can work around making linefilter def instead of val, expected behavior? doesn't seem right problem should become apparent after getting npe @ runtime.

it indeed expected behavior, , same problem in question:

scala 2.8: how initialize child class

you can copy-paste answer form question. solutions include:

• def or lazy val instead of val
• early initialization of linefilter

• redesign of classes avoid “virtual method call superclass's constructor accesses uninitialized subclass values” problem. instance, why want store filter function in val or return in def, while implemented method?

  abstract class genericparser[t] {   def linefilter(line: string): boolean    parsedata()    def parsedata() : t {     for( line <- .... if linefilter(line) )       // things   } }  class salesparser extends genericparser[salesrow] {   def linefilter(line: string) = !line.startswith("//") }