Unlocking Elixir Magic: Creating and Documenting Custom Sigils

Sigils in Elixir are a powerful tool for working with different data types. In this guide, we'll dive into the enchanting realm of creating and documenting custom sigils to enhance your Elixir coding experience.

Creating Custom Sigils

defmodule MySigils do
  # Returns the downcased string; if option 'l' is given, returns the list of downcased letters
  def sigil_l(string, []), do: String.downcase(string)
  def sigil_l(string, [?l]), do: String.downcase(string) |> String.graphemes
 
  # Returns the upcased string; if option 'l' is given, returns the list of upcased letters
  def sigil_u(string, []), do: String.upcase(string)
  def sigil_u(string, [?l]), do: String.upcase(string) |> String.graphemes
end

These custom sigils (~l and ~u) are designed to downcase or upcase a string, respectively. The magical part is that if the option ~l is provided, they return a list of individual letters.

Usage

Load the module into your IEx:

iex> import MySigils
iex> ~l/HELLO/
"hello"
iex> ~l/HELLO/l
["h", "e", "l", "l", "o"]
iex> ~u/hello/
"HELLO"
iex> ~u/hello/l
["H", "E", "L", "L", "O"]

By creating and utilizing these custom sigils, you unlock a new level of expressiveness and convenience in your Elixir code. Documenting their usage ensures a seamless experience for both you and anyone who interacts with your magical Elixir spells.