toraritte

# lib/witchcraft/monoid.ex

  properties do
    def left_identity(data) do
      a = generate(data) 
    # a == TypeClass.Property.Generator.Function.generate(data)
    # but that input will get ignored.

      if is_function(a) do
        equal?(Semigroup.append(Monoid.empty(a), a).("foo"), a.("foo"))

toraritte

defmodule TypeClass.Property do
  @moduledoc "A *very* simple prop checker"

  # (...)
  
  @doc "Run all properties for the type class"
  def run!(datatype, class, prop_name, times \\ 100) do
    property_module  = Module.concat(class, Property)
    
    # Irrelevant parts in this scenario are commented out.

toraritte

defmodule TypeClass do
  # (...)
  
  defmacro definst(class, opts, do: body) do
    [for: datatype] = opts

    quote do

      # The type  class protocol's  instance implementation  goes  into
      # `type_class.Proto.datatype` (in the case of `Monoid`, this will 

toraritte

import TypeClass

  ################
  # DEPENDENCIES #
  ################
  extend Witchcraft.Semigroup, alias: true
  
  ############
  # PROTOCOL #
  ############

toraritte

Associativity

Group-like structures
	Totalityα

toraritte

defmodule Aquir.Users.Read.Schemas.User do
  use Ecto.Schema
  alias Aquir.Users.Read.Schemas, as: RS

  @primary_key {:user_id, :binary_id, autogenerate: false}

  schema "users" do

    has_one :credential, RS.UsernamePasswordCredential,
      foreign_key: :user_id

toraritte

What is the specific syntax of @derive module attribute and where is it documented explicitly?

NOTE: All links to the Elixir github repo and documentation are fixed to version 1.7.4.

"Elixir allows us to derive a protocol implementation based on the Any implementation"² using @derive. The [Kernel.@/1][2] macro compiles to a call to [Module.get_attribute/2][3] function³.

Progress

Got bogged down looking at Kernel.@/1 definition: what is does the curly brace do in the definition? (i.e., defmacro @{..})

toraritte

/* Understanding iOS views*/

/* In ViewController.swift after creating a Single View App. */
import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

toraritte

# Mixing `Agent.cast/2` and `Agent.update/3`

# Ignoring the state here, hence `:ok`
Agent.start_link(fn -> :ok end, name: :lofa)

f = fn (command, t) ->
      apply(Agent, command, [
        :lofa,
        fn _ -> # becuase state is ignored
          Process.sleep(t)

toraritte

defmodule UniqueUsername do
  use Agent

  def start_link(_) do
    Agent.start_link(fn -> MapSet.new() end, name: __MODULE__)
  end

  def claim(name) do
    name_is_taken = Agent.get(__MODULE__, &MapSet.member?(&1, name))