Can someone explain me implicit conversions in Scala?

Question

And more specifically how does the BigInt works for convert int to BigInt?

In the source code it reads:

...
implicit def int2bigInt(i: Int): BigInt =         


        

Answer 1

Complementing @GClaramunt's answer.

Because it's way simpler to understand and grasp this concept by seeing a full example:

// define a class
case class Person(firstName: String, lastName: String)

// must import this to enable implicit conversions
import scala.language.implicitConversions

// define the implicit conversion. String to Person in this case
implicit def stringToPerson(name:String) = {
  val fields = name.split(" ");
  Person(fields(0), fields(1))
}

// method using the implicit conversion  
def getPerson(fullName:String): Person = fullName

val fooBar = getPerson("foo bar")
println(fooBar.getClass())  // class Person
println(fooBar.firstName)  // foo
println(fooBar.lastName)  // bar

I hope this example clarifies why and how one would want to use implicit conversions (not that I think converting String to Person makes a lot of sense but it's worth the illustration).