richard-gibson

Advanced Functional Programming with Scala - Notes

Copyright © 2017 Fantasyland Institute of Learning. All rights reserved.

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

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import scala.reflect.ClassTag

//ClassTag will make type info available that is erased by the JVM at runtime

def filterT[T :ClassTag](t:Any) : Boolean = t match {
  case _:T => true
  case _ => false
}

val anyL = List(1,"fe", 2, 3, 'a')

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val examinePattern: (String, String, String) => String = {
    case (pattern, "", _) => pattern
    case (pattern, tail, orig) if tail.take(pattern.length) == pattern =>
      examinePattern(pattern, tail.drop(pattern.length), orig)
    case (pattern, _, orig) =>
      examinePattern(orig.take(pattern.length + 1), orig, orig)
  }


val runEp : String  => String =

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Add to ~/.ssh/config

Host github.com-foo
    HostName github.com
    User git
    IdentityFile ~/.ssh/id_rsa_foo

Host github.com-bar
 HostName github.com

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object MagnetExample extends App {

  sealed trait AdditionMagnet {
    type Result
    def apply():Result

  }

  object AdditionMagnet {

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no_funs({M, _}) ->
  {M,length(M:module_info(exports))}.

max_funs({Lm,Lsize},{Rm,Rsize}) ->
  case Lsize =< Rsize of
    true -> {Rm,Rsize};
    false -> {Lm,Lsize}
  end.

largest_module(Modules) ->