This document covers some naming conventions in Elixir code, from casing to punctuation characters. Casing Elixir developers must use snake_case when defining variables, function names, module attributes, etc.: some_map = %{this_is_a_key: "and a value"} is_map(some_map) Aliases, commonly used as module names, are an exception as they must be capitalized and written in CamelCase, like OptionParser.