"Make your programs free" presented at Scala Matsuri

1. Make your programs Free
Pawel Szulc
@rabbitonweb

3. Free Monads!

4. Free[S, A]

5. Free[S, A]
This is the program

6. Free[S, A]
This is the language

7. Free[S, A]
This is the type of a value it will produce (once it is run)

8. Let’s see it in action!
(aka Demo)
https://github.com/rabbitonweb/make-your-programs-free

9. Usage of Scalaz’s Task
class Task[+A](val get: Future[Throwable / A]) { .. }

10. Usage of Scalaz’s Task
class Task[+A](val get: Future[Throwable / A]) { .. }
def foo(input: Int): Future[String]

11. Usage of Scalaz’s Task
class Task[+A](val get: Future[Throwable / A]) { .. }
def foo(input: Int): Future[String]
def bar(intput: Int): Task[String]

12. Usage of Scalaz’s Task
class Task[+A](val get: Future[Throwable / A]) { .. }
def foo(input: Int): Future[String]
def bar(intput: Int): Task[String]
val f: Future[String] = foo(10)
val b: Task[String] = bar(20)
val s1: String = b.unsafePerformSync

13. Let’s see it in action!
(aka Demo)
https://github.com/rabbitonweb/make-your-programs-free

14. Input - Output

49. Logging

60. Can we have both?

85. Manipulate Account

125. Introducing: low level
machinery

133. Compiling down to
lower-level language

144. Free[S, A]

145. But I want to see a real world example!
https://github.com/quasar-analytics/quasar

146. Thank you for watching!
Pawel Szulc
@rabbitonweb

147. Thank you for watching!
Pawel Szulc
@rabbitonweb
paul.szulc@gmail.com

148. Thank you for watching!
Pawel Szulc
@rabbitonweb
paul.szulc@gmail.com
http://rabbitonweb.com

149. Thank you for watching!
Pawel Szulc
@rabbitonweb
paul.szulc@gmail.com
http://rabbitonweb.com
https://github.com/rabbitonweb/make-your-programs-free