JoelQ

Ruby docs for Array#uniq

From the docs:

uniq → new_ary uniq { |item| ... } → new_ary Returns a new array by removing duplicate values in self.

If a block is given, it will use the return value of the block for comparison. It compares values using their hash and eql? methods for efficiency.

JoelQ

What is Elm

Pure Functions

What does that mean?

• For a given input, you always get the same output
• The output cannot depend on any external factors (e.g. File on disk, some external variable)

JoelQ

namespace :dependencies do
  task :pre_task do
    puts "pre-task"
  end

  task task1: :pre_task do
    puts "task1"
  end

  task task2: :pre_task do

JoelQ

port module Main exposing (..)

import Html.App
import Html exposing (..)
import Html.Attributes exposing (id)


type alias Row =
    List String

JoelQ

module Main exposing (..)

import Array
import Tuple
import Dict exposing (Dict, get)
import Random exposing (Generator, map)


-- RANDOM

JoelQ

What's up with Html a?

Ever wonder why sometimes the compiler yells at you for using type Html a ? Why is a ok some times but not others?

It's not unique to Html a. Look at the same problem using a simpler type we all understand: List a.

Here are a few questions and thoughts to ponder:

• Compare the myList and myHtml functions. How are they similar? How are they different?
• Why do you think these functions will compile or not compile?

JoelQ

User = Struct.new(:name, :age, :profession)

class MonoidBuilder
  def initialize(name: nil, age: nil, profession: nil)
    @name = name
    @age = age
    @profession = profession
  end

  def self.empty

JoelQ

Mapping the world

Abstract

Provide a concise description for the program limited to 600 characters or less.

From the earliest cave paintings to today's GPS-assisted smartphone apps, maps have been an important part of we have described the world around us. But what goes into turning the life-size 3d world into a 2d image that fits in your

JoelQ

Modeling Data with Algebraic Data Types

Abstract

Provide a concise description for the program limited to 600 characters or less.

What is "good code"? You've probably heard something like "readable, easy to change, modular, and correct". But what does that look like in practice?

JoelQ

Script to generate domain-specific Elm types wrapping primitives (see https://robots.thoughtbot.com/lessons-learned-avoiding-primitives-in-elm for why this is a good idea)

Use looks like:

% ./create_newtype Email String > email.elm

module Email exposing (Email, fromString, toString, map, map2)