CODEWITHSUNDEEP
scalasupermethod-call
noncom
noncom

Reputation: 4992

Scala, call instance method right from superconstructor call?

Suppose I have the following Scala code:

class Foo(a: Int)

class Bar(b: Buffer[Int]) extends Foo (sum) {

  def sum = (1 /: b)(_ + _)

}

why does it complain on calling the method sum from the constructor? Is it not possible to get such a behavior with such simple implementation at all? I realize that I could make a companion object for Bar but that is not exactlywhat would I do?

PS there is no 'superconstructor' tag!)))

UPDATE: What are possible alternatives?

Upvotes: 2

Views: 420

Answers (2)

Daniel C. Sobral
Daniel C. Sobral

Reputation: 297265

if sum is not being called on a Bar instance -- and it isn't, since it hasn't been constructed yet! -- then its place is definitely not inside Bar. If Bar is its sole user, then the natural place for it is the companion object.

The more interesting question is why you don't want it in its natural place?

Upvotes: 1

agilesteel
agilesteel

Reputation: 16859

Each time an instance of Bar is being constructed all its members are being added to it. Only after the construction is complete can you call its members.

Upvotes: 3

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