JoelQ

# This imagines `.unfold` to be an alternate constructor for `Enumerator` that's
# more complex than `.produce` but not as custom as the full `.new`. It follows the rules
# of anamorphisms (at least for arrays, not sure if this genericises to other structures)
class CustomEnumerator
  def self.unfold(seed, &block)
    Enumerator.new do |yielder|
      loop do
        seed, value = block.call(seed)
        raise StopIteration if value.nil?

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

class Tree
  attr_reader :val, :left, :right

  def self.empty
    EmptyTree.new
  end

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

JoelQ

-- 0.19

randomToTask : Generator a -> Task x a
randomToTask generator =
    Time.now
        |> Task.map (Tuple.first << Random.step generator << Random.initialSeed << Time.posixToMillis)


-- 0.18

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 Tally
  def self.empty
    new({})
  end

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

  # Accessors

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.