doolin

class Tree
  attr_reader :val, :left, :right

  def self.empty
    EmptyTree.new
  end

  def self.leaf(val)
    new(val, empty, empty)
  end

doolin

# need to "pin" the variable, but this only works with the lambda because
# pattern matching falls back to case matchint (=== on any object in ruby,
# which is NOT "identical object" as in JS)
def matches1(pat,x)
  case x
  in ^pat
    puts true
  else
    puts false
  end

doolin

Falsehoods programmers believe about time

This is a compiled list of falsehoods programmers tend to believe about working with time.

Don't re-invent a date time library yourself. If you think you understand everything about time, you're probably doing it wrong.

Falsehoods

• There are always 24 hours in a day.
• February is always 28 days long.
• Any 24-hour period will always begin and end in the same day (or week, or month).

doolin

This is a very quick gist I'm throwing together to get this info and discussion onto google in one place.

For years, people have been using jemalloc with ruby. There are various benchmarks and discussions. Some people say Jemalloc 5 doesn't work as well as Jemalloc 3.

Then, one day, hope appeared on the horizon. Someone offered a config for Jemalloc 5.

The recipe would be something like this (shown with official docker ruby image). I didn't try this yet, don't know if it will build!

doolin

require "openssl"
require "digest"

def aes128_cbc_encrypt(key, data, iv)
  key = Digest::MD5.digest(key) if(key.kind_of?(String) && 16 != key.bytesize)
  iv = Digest::MD5.digest(iv) if(iv.kind_of?(String) && 16 != iv.bytesize)
  aes = OpenSSL::Cipher.new('AES-128-CBC')
  aes.encrypt
  aes.key = key
  aes.iv = iv

doolin

require 'openssl'
require 'base64'
require 'rexml/document'

class PKeyRSAConverter
  def initialize(from_pem: nil, from_xml: nil)
    @from_pem = from_pem
    @from_xml = from_xml
  end

doolin

#!/usr/bin/ruby
require 'openssl'

TYPES = {
  6 => {magic: 'RSA1', private_key: false},
  7 => {magic: 'RSA2', private_key: true}
}

data = ARGV[0] ? File.binread(ARGV[0]) : $stdin.binmode.read
type, version, algo, magic, bits, rest = data.unpack('ccx2l<a4l<a*')

doolin

class Orders < ActiveRecord::Migration[7.0]
  def change
    create_table :orders do |t|
      t.string :first_name # use Rails validations
      t.string :last_name, null: false, limit: 128
    end
  end
end
Orders.migrate(:up) unless Orders.data_source_exists?(:orders)

doolin

class Order
  include ActiveModel::Validations

  attr_reader :name

  validates :name, presence: true

  def initialize(name)
    @name = name
  end

doolin

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'active_record'
require 'rspec/autorun'
require 'pg'
require 'byebug'

# Extend for effect
class String