Alfred Freitas luanrjjj

Open Source Business Challenges and Reality

Original Japanese note here.

Original Author: Rui Ueyama (creator of the mold linker)

Translated by @windowsboy111

Minimally edited by @lleyton

Let's say you need to handle the following action:

class UsersController < ApplicationController
  def update
    user = User.find(id)
    result = update_user(user, attrs)

You're taking your first steps into Ruby

A good introduction to programming in general. Easy on newer programmers.

# Ubuntu
sudo apt-get install gpa seahorse
# MacOS with https://brew.sh/

In Ruby, a Symbol is the most efficient way, in terms of time and memory, to represent a set of characters.

Most commonly, a Symbol is a single word prefixed by a colon:

:hello

	Measure = Data.define(:amount, :unit) do
	def diff(other)
	raise ArgumentError.new("other must be same class") unless other.is_a?(self.class)

	members.inject({}) do \|memo, key\|
	thisVal, otherVal = send(key), other.send(key)
	memo[key] = [thisVal, otherVal] unless thisVal == otherVal

	memo
	end

	# Using OpenStruct to mimic an object with the 'posts method'
	user = OpenStruct.new(posts: [:post1, :post2])

	# Using if user as a nil checker
	user.posts if user
	# => [:post1, :post2]

	# Can be replaced with the safe navigation operator
	user&.posts
	# => [:post1, :post2]

	#!/usr/bin/env ruby
	require 'pdf/reader' # gem install pdf-reader

	# credits to :
	# https://github.com/yob/pdf-reader/blob/master/examples/text.rb
	# usage example:
	# ruby pdf2txt.rb /path-to-file/file1.pdf [/path-to-file/file2.pdf..]
	ARGV.each do \|filename\|

	PDF::Reader.open(filename) do \|reader\|