defmodule NLdoc.Test.EmptyText do
  @moduledoc """
  This module provides a list of strings that are considered empty texts, i.e. they are non-discernable: they are either invisible or look like whitespace.
  """
  @empty_texts [
    "",
    " ",
    "        ",
    nil,
    # Newline (LF)
    "\n",
    # Tab (HT)
    "\t",
    # Carriage return (CR)
    "\r",
    # Backspace
    "\b",
    # Form feed (FF)
    "\f",
    # Vertical tab (VT)
    "\v",
    # Next line (NEL)
    "\u0085",
    # Non-breaking space
    "\u00A0",
    # Ogham space mark
    "\u1680",
    # Mongolian vowel separator
    "\u180E",
    # En quad
    "\u2000",
    # Em quad
    "\u2001",
    # En space
    "\u2002",
    # Em space
    "\u2003",
    # Three-per-em space
    "\u2004",
    # Four-per-em space
    "\u2005",
    # Six-per-em space
    "\u2006",
    # Figure space
    "\u2007",
    # Punctuation space
    "\u2008",
    # Thin space
    "\u2009",
    # Hair space
    "\u200A",
    # Zero-width space
    "\u200B",
    # Zero-width non-joiner
    "\u200C",
    # Zero-width joiner
    "\u200D",
    # Line separator
    "\u2028",
    # Paragraph separator
    "\u2029",
    # Narrow no-break space
    "\u202F",
    # Medium mathematical space
    "\u205F",
    # Word joiner
    "\u2060",
    # Ideographic space
    "\u3000",
    # Byte Order Mark (BOM) / Zero-Width Non-Breaking Space
    "\uFEFF"
  ]

  @doc """
  Forms of empty texts for use in tests.

  ## Examples

      iex> NLdoc.Test.EmptyText.all() |> Enum.member?(" ")
      true
  """
  def all, do: @empty_texts
end