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Learning Scala Programming

You're reading from   Learning Scala Programming Object-oriented programming meets functional reactive to create Scalable and Concurrent programs

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Product type Paperback
Published in Jan 2018
Publisher Packt
ISBN-13 9781788392822
Length 426 pages
Edition 1st Edition
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Author (1):
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Vikash Sharma Vikash Sharma
Author Profile Icon Vikash Sharma
Vikash Sharma
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Table of Contents (16) Chapters Close

1. Getting Started with Scala Programming FREE CHAPTER 2. Building Blocks of Scala 3. Shaping our Scala Program 4. Giving Meaning to Programs with Functions 5. Getting Familiar with Scala Collections 6. Object-Oriented Scala Basics 7. Next Steps in Object-Oriented Scala 8. More on Functions 9. Using Powerful Functional Constructs 10. Advanced Functional Programming 11. Working with Implicits and Exceptions 12. Introduction to Akka 13. Concurrent Programming in Scala 14. Programming with Reactive Extensions 15. Testing in Scala 16. Other Books You May Enjoy

The implicitly method


Scala's standard library provides a utility method to create concrete instances of types' availability implicitly. The method's name is also implicitly. Let's take a look at the function signature:

def implicitly[T](implicit e: T) = e 

This implicitly method simply expects a type parameter, finds the implicit value available in scope, and summons and returns it to us. This is a good option available to us to tell whether a particular type's value is available in implicit scope. Let's look at an application of this method:

import java.time.{LocalDateTime} 
 
object ImplicitParameter extends App { 
 
  implicit val dateNow = LocalDateTime.now() 
 
  def showDateTime(implicit date: LocalDateTime) = println(date) 
 
  val ldt = implicitly[LocalDateTime] 
 
  println(s"ldt value from implicit scope: $ldt") 
} 

The following is the result:

ldt value from implicit scope: 2017-12-17T10:47:13.846 

In the preceding code snippet, a call to implicitly, along with the type, returned us...

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