JoelQ

class Tally
  def self.empty
    new({})
  end

  def initialize(raw)
    @raw = empty_hash.merge raw.slice(:small, :medium, :large)
  end

  # Accessors

JoelQ

Elm Types Glossary

There's a lot of type terminology and jargon going around when discussing types in Elm. This glossary attempts to list some of the most common type terms along with synonyms, terms from other language communities, examples, and links to more detailed articles on each topic.

• Custom Type
• Constructor
• Unit Type

JoelQ

class Dollar
  attr_reader :cents

  def initialize(cents:)
    @cents = cents
  end

  def hash
    [self.class, cents].hash
  end

JoelQ

require "date"

class Month
  include Comparable

  MONTHS_PER_YEAR = 12

  def self.from_date(date)
    self.from_parts(date.year, date.month)
  end

JoelQ

Refactoring maybe code in Elm

Given this ugly series of cases:

optionalFormattedFriendAddress : Maybe Friend -> Maybe String
optionalFormattedFriendAddress maybeFriend =
  let
    maybeAddress = case maybeFriend of
      Just friend -> Just friend.address

JoelQ

Server scripts

This is the source for the scripts discussed in https://robots.thoughtbot.com/improving-user-experience-with-shell-scripts

Both scripts are in the bin/ directory of the repo that contains all the markdown documents for blog posts. Users run bin/server and everything is automatically set up for them to view a local preview of the blog. bin/server-setup is a dependency of bin/server and is never run directly by users.

Maitre-d is the name of the "blog engine" discussed in the article.

JoelQ

How not to implement a multi-step form

"That ticket touches the wizard code? Why don't YOU take that one". The wizard in question is so gnarly my colleagues are afraid to touch it.

Looking at the code through the lens of conditional cardinality reveals what went wrong and how we can make things better. This mental model will change the way you think about structuring logic and help you take your conditional code from scary to delightful.

Description

This talk is aimed at an intermediate to advanced audience. While it will driven by a practical example (refactoring a multi-step form), it will mainly be about some more theoretical principles and mental models for structuring conditional code.

JoelQ

The Math Every Programmer Needs

Abstract

Leave your fear of math behind along with the equations and symbols, we're headed to Ruby-land! On this whirlwind tour, we’ll explore how to write better conditionals with Boolean algebra, figure out how many test cases we need with combinatorics, a mental model for breaking down large tasks with graph theory, and more.

You’ll leave this talk equipped to better do your job with some ideas, techniques, and mental models from the wonderfully practical world of discrete math.

Details

JoelQ

class Tree
  attr_reader :val, :left, :right

  def self.empty
    EmptyTree.new
  end

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

JoelQ

Generic Elm types exercises

A series of exercises to get a feel for how generic types and type variables work in Elm. For each of these, you are given some code that is not compiling. Your task is to get it compiling. You can change the body of the function but not the signature. No cheating with Debug.todo or infinite recursions either 😉

• List
• Maybe
• Html