mikamix

始代数とcatamorphism

---

自己紹介

• 三上遼
• 0x20歳
• IoTの会社でスマートロック作ってます
• 数学弱いです

mikamix

class Num
  def initialize(v)
    @v = v
  end

  def combine(target)
    target
  end
end

mikamix

module Monad where                                                                                                     
                                                                                                                       
import Prelude hiding (fmap, Functor, Monad)                                                                           
                                                                                                                       
class Functor f where                                                                                                  
                                                                                                                       
  fmap :: (a -> b) -> f a -> f b                                                                                       
                                                                                                                       
class Functor m => Applicative m where                          

mikamix

declare
fun {Fact N}
   if N == 0 then 1 else N * {Fact N - 1} end
end

declare
fun {AddList L1 L2}
   case L1 of H1 | T1 then
      case L2 of H2 | T2 then
	 H1 + H2 | {AddList T1 T2}

mikamix

module Main

data FizzBuzz : (n: Nat) -> Type where
  Zero : FizzBuzz n
  Fizz : FizzBuzz n
  Buzz : FizzBuzz n
  Woof : FizzBuzz n
  Comb : FizzBuzz n -> FizzBuzz n -> FizzBuzz n

instance Semigroup (FizzBuzz n) where

mikamix

def pascal1(c: Int, r: Int): Int = {
  if (c == 0 || c == r) 1
  else pascal1(c - 1, r - 1) + pascal1(c, r - 1)
}

def pascal2(c: Int, r: Int): Int = {

  @tailrec
  def pascal(n: Int, prev: List[Int]): Int = {
    val row = (0 :: prev).zipAll(prev, 0, 0).map(t => t._1 + t._2)

mikamix

!SLIDE

YCombinator

!SLIDE

YCombinatorとは何か

!SLIDE

ベンチャーキャピタル

YコンビネータLLC（Y Combinator LLC）は、カリフォルニア州マウンテンビューのベンチャーキャピタルである。

mikamix

import Data.Char

euler16 = sum . (map digitToInt) . show

main = print $ euler16 (2 ^ 1000)

mikamix

combination n r = factorial n `div` (factorial (n - r) * factorial r)
  where factorial 1 = 1
        factorial n = n * factorial (n - 1)

main = print $ combination 40 20

mikamix

(define (union-set set1 set2)
  (cond ((null? set1) set2)
        ((null? set2) set1)
        (else (let ((x1 (car set1)) (x2 (car set2)))
                (cond ((< x1 x2) (cons x1 (union-set (cdr set1) set2)))
                      ((> x1 x2) (cons x2 (union-set set1 (cdr set2))))
                      (else (cons x1 (union-set (cdr set1) (cdr set2)))))))))