Programming Elixir Chapter 25 Notes

Writing Your Own Sigils

1. Lowercase sigils interpolate their parameters, uppercase sigils do not.

2. User-defined sigils are not globally available. Need to be imported. Reduces the risk of running into a system-defined sigil.

Multi-app Umbrella Projects

There seems to be some community disagreement about umbrella projects. My basic understanding is that it is likely not something I should consider except for extremely large and/or complex projects.

MoreCoolStuff-1

Write a ~v sigil that parses multiple lines of csv data. Return a list of lists.

defmodule CsvSigil do
  @doc """
  Implement the `~v` sigil to parse rows of comma-separated data into a list of lists.
  Ignore any spaces before commas and trailing commas.
  Allows interpolation.

  ## Example usage
      iex> import CsvSigil
      iex> ~v"""
      ...>1,2,#{3}
      ...>cat,dog
      ...>"""
      [["1","2","3"], ["cat","dog"]]
  """

  def sigil_v(lines, _opts) do
    lines
    |> String.trim_trailing
    |> String.split("\n")
    |> Enum.map(fn x -> String.split(x, ",") end)
  end
end