kerryb

Concurrency in Elixir

Mix.install([
  {:kino, "~> 0.12.3"}
])

Basic message passing with send and receive

kerryb

Changeset/Form issue

Mix.install([
  {:phoenix_live_view, "~> 0.20.1"},
  {:phoenix_ecto, "~> 4.4"}
])

Create a struct

kerryb

class Stack

  class Empty < RuntimeError; end

  def initialize
    @items = []
  end

  def empty?
    @items.count == 0

kerryb

text
|> String.split("\n")
|> Enum.reduce({["{"], "    "}, fn line, {output, current_indent} ->
  case Regex.run(~r/^( +)(.*): ?(.*)/, line, capture: :all_but_first) do
    [indent, key, ""] ->
      close_braces =
        if indent < current_indent do
          Enum.map_join(
            (String.length(current_indent) - 4)..String.length(indent)//-4,
            "",

kerryb

#!/usr/bin/env elixir

Mix.install([
  {:httpoison, "~> 1.8"},
  {:jason, "~> 1.3"}
])

defmodule Space do
  def run do
    fetch_data()

kerryb

defmodule MyApp.Repo do
  require Logger
  alias Ecto.Association.NotLoaded
  alias Ecto.{Changeset, Schema}
  alias MyApp.Auth.User

  ...

  @doc """
  Wrapper round `Ecto.Repo.insert/2`, which logs the fields of the inserted

kerryb

README

A spike looking at adding basic given-when-then steps to ExUnit tests.

Features

• define tests as sequences of calls to given_, when_ and then_ (unfortunately when is a reserved word)
• match steps by calling defwhen etc with a string matching the one used in the step
• interpolate values into step descriptions using {braces}
• placeholder variable names are available as methods on the magic args variable

kerryb

defmodule Child do
  def task(parent) do
    Process.sleep(:timer.seconds(2))
    send(parent, :finished)
  end
end

kerryb

ytd() {
  ytd=$(find ~/Dropbox/Apps/tapiriik -name $(date +%Y)-*_Running*.tcx -print0 | xargs -0 -n1 awk '/DistanceMeters/ {a=$0} END {gsub(/\s*<[^>]*>/, "", a); print a}' | paste -sd+ - | sed 's/\(.*\)/0.000621371 * (\1)/' | bc | sed 's/\(\..\).*/\1/')
  proj=$(echo "$ytd * 365 / $(date +%j)" | bc)
  echo "YTD: $ytd. Projected: $proj"
}

kerryb

class RomanNumerals
  NUMBERS = {
    1000 => "M",
    900 => "CM",
    500 => "D",
    400 => "CD",
    100 => "C",
    90 => "XC",
    50 => "L",
    40 => "XL",