The implicit keyword in Scala

 Here's an example of how to use the implicit keyword in Scala:

kotlin

class Person(val name: String)

case class Book(title: String, author: String)

object Library {

  implicit val defaultPerson = new Person("Unknown")

  def borrow(book: Book)(implicit person: Person): String = {

    s"${person.name} has borrowed ${book.title} by ${book.author}"

  }

}

import Library._

val book = Book("The Hitchhiker's Guide to the Galaxy", "Douglas Adams")

val borrower = new Person("Arthur Dent")

println(borrow(book)(borrower))

println(borrow(book))

In this example, the Person class represents a person with a name, and the Book case class represents a book with a title and author. The Library object defines a borrow method that takes a Book object and an implicit Person object, and returns a string describing who has borrowed the book.

The defaultPerson value is marked as implicit, which means that if no Person object is explicitly provided when calling the borrow method, the default value will be used instead. This allows the borrow method to be called without providing a Person object explicitly, as shown in the second println statement.

The import Library._ statement is used to import the borrow method and the defaultPerson value into the current scope, so they can be used without fully qualifying their names.

This example demonstrates how the implicit keyword can be used to define default values for method parameters, and how they can be used automatically if no value is explicitly provided. It also shows how importing values into the current scope can make code more concise and readable.