jdegoes

Applied Functional Programming with Scala - Notes

Copyright © 2016-2018 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

bkyrlach

object Jealousy {
  import Scalog._
  def main(args: Array[String]): Unit = {
   implicit val knowledge = 
     Functor("loves", "vincent", "mia") ::
     Functor("loves", "marsellus", "mia") ::
     Functor("loves", "pumpkin", "honey_bunny") :: 
     Functor("loves", "honey_bunny", "pumpkin") :: 
     Rule(Functor("jealous", "X", "Y"), Functor("loves", "X", "Z") and Functor("loves", "Y", "Z")) ::
     Nil

ckirkendall

(use '[clojure.core.match :only [match]])

(defn evaluate [env [sym x y]]
  (match [sym]
    ['Number]   x
    ['Add]      (+ (evaluate env x) (evaluate env y))
    ['Multiply] (* (evaluate env x) (evaluate env y))
    ['Variable] (env x)))
    
(def environment {"a" 3, "b" 4, "c" 5})