Sigils

Sigils

A sigil is a tilde with a character.

Sigil	Generates..
~C	..a character list with no escaping nor interpolation
~c	..a character list with escaping and interpolation
~R	.. a regular expression with no escaping or interpolation
~r	.. a regular expression with escaping and interpolation
~S	.. a string with no escaping or interpolation
~s	.. a string with escaping and interpolation
~W	.. a word list with no escaping or interpolation
~w	.. a word list with escaping and interpolation
~N	.. a NaiveDateTime struct
~U	.. a DateTime struct (since Elixir 1.9.0)
~D	converts to date which can be accessed by .day .year .month

Sigils are used with delimiters:

<…> A pair of pointy brackets {…} A pair of curly brackets […] A pair of square brackets (…) A pair of parentheses |…| A pair of pipes /…/ A pair of forward slashes “…” A pair of double quotes ‘…’ A pair of single quotes

Char List

~c/2 + 7 = #{2 + 7}/ #interpolates
'2 + 7 = 9'

~C/2 + 7 = #{2 + 7}/ #does not interpolate
'2 + 7 = \#{2 + 7}'

Regex

re = ~r/elixir/
~r/elixir/

iex> "Elixir" =~ re
false

iex> "elixir" =~ re
true

string = "100_000_000"
"100_000_000"

iex> Regex.split(~r/_/, string) # ~r/_/ splits the _ and .split turns it to a list
["100", "000", "000"]

String

~s/welcome to elixir #{String.downcase "SCHOOL"}/
"welcome to elixir school"

~S/welcome to elixir #{String.downcase "SCHOOL"}/
"welcome to elixir \#{String.downcase \"SCHOOL\"}"

Word List

iex> ~w/i love #{'e'}lixir school/
["i", "love", "elixir", "school"]

iex> ~W/i love #{'e'}lixir school/
["i", "love", "\#{'e'}lixir", "school"]

NaiveDateTime

NaiveDateTime.from_iso8601("2015-01-23 23:50:07") == {:ok, ~N[2015-01-23 23:50:07]}

DateTime

DateTime.from_iso8601("2015-01-23 23:50:07Z") == {:ok, ~U[2015-01-23 23:50:07Z], 0}
DateTime.from_iso8601("2015-01-23 23:50:07-0600") == {:ok, ~U[2015-01-24 05:50:07Z], -21600}

Custom Sigils

defmodule MySigils do
  def sigil_p(string, []), do: String.upcase(string)
end

import MySigils
nil

~p/elixir school/
ELIXIR SCHOOL