CODEWITHSUNDEEP
scalaviewimplicit
Norswap
Norswap

Reputation: 12202

Scala: Implicit Conversion via a method (e.g. toString)

In Scala, I'd like to do:

class Identifier(val str: String) {
    override def toString(): String = str
}

class Variable(t: Type, name: Identifier, mutable: Boolean) {
    override def toString(): String = name
}

But I can't because Scala won't implicitly convert name in Variable#toString()'s definition to a String. Is there a way this can be achieved ?

To be clear: I don't want to define an additional method like:

object Identifier {
    implicit def idToString(x: Identifier): String = x.str
}

I'd like the toString() method to be called to do the conversion.

Upvotes: 4

Views: 2551

Answers (3)

andy
andy

Reputation: 1715

If you just want 'odd' ways of doing this then you can use member import

class Variable(t: Type, name: Identifier, mutable: Boolean) {
  import name.{toString => toStr}
  override def toString(): String = toStr
}

you cannot do import name.toString as this gets hidden by all other toStrings methods in Any etc

Upvotes: 1

virtualeyes
virtualeyes

Reputation: 11237

override def toString(): String = name.toString

is not terribly taxing on the fingers

Upvotes: 0

Jens Egholm
Jens Egholm

Reputation: 2710

Try putting an explicit toString() call after calling name in Variables toString method like so:

override def toString() = name.toString()

Here you will explicitly call the method converting Variable to a string, thus telling the compiler exactly what you want.

.. Unless you really require the method to be implicit...

Upvotes: 6

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