SyunWatanabe

// useReducer
// https://ja.reactjs.org/docs/hooks-reference.html#usereducer

// basic
// const [state, dispatch] = useReducer(reducer, initialArg, init);

// reducer type
// (state, action) => newState;

// when it use??

SyunWatanabe

// ==UserScript==
// @name         show meta
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  show meta what we want
// @author       me
// @match        *://*/*
// @grant        none
// ==/UserScript==

SyunWatanabe

# Ruby Document
# https://docs.ruby-lang.org/ja/latest/class/Enumerable.html#I_PARTITION

# github: holiday_japan
# https://github.com/masa16/holiday_japan/blob/master/lib/holiday_japan.rb

require 'holiday_japan'

# Enumerable#partitionを使い2020年の祝日がある月を抽出する

SyunWatanabe

# frozen_string_literal: true

# block

# simple
def say_fact
  if block_given?
    puts 'i got block'
  else
    puts 'i need block'

SyunWatanabe

# count 再実装
class Array
  def count(*args)
    if block_given?
      num = 0
      each { |i| num += 1 if yield(i) }
      num
    elsif args.empty?
      size
    else

SyunWatanabe

# 例外処理 サンプルそのまま
print "Text?:"
text = gets.chomp
begin
  print "Pattern?:"
  pattern = gets.chomp
  regexp = Regexp.new(pattern)
rescue RegexpError => e
  puts "Invalid regexp #{e.message}"
  retry

SyunWatanabe

# Moduleを使う DeepFreeze(自作)
module Freeze
  def deep_freeze(object)
    object.freeze
    object.each do |element, value|
      element.freeze
      value&.freeze
    end
  end
end

SyunWatanabe

# 改札機プログラム（自力作）

STATION = ['harajyuku', 'omotesando', 'nogizaka']

class Gate
  attr_accessor :name

  def initialize(name)
    @name = name
  end

SyunWatanabe

# 正規表現変換

old_syntax = <<TEXT
{
  :name => 'Alice',
  :age=>20,
  :gender  =>   :female
}
TEXT

SyunWatanabe

# 長さの単位変換プログラム
def convert_length(num, unit, conversion)
  hash = {'m' => 1.00, 'ft' => 3.28, 'in' => 39.37}
  (num * hash[conversion] / hash[unit]).round(2)
end

puts convert_length(1, 'm', 'in')
puts convert_length(15, 'in', 'm')
puts convert_length(35_000, 'ft', 'm')