Regex.compile
You're seeing just the function
compile, go back to Regex module for more information.
Specs
Compiles the regular expression.
The given options can either be a binary with the characters
representing the same regex options given to the
~r (see Kernel.sigil_r/2) sigil, or a list of options, as
expected by the Erlang's :re module.
It returns {:ok, regex} in case of success,
{:error, reason} otherwise.
Examples
iex> Regex.compile("foo")
{:ok, ~r/foo/}
iex> Regex.compile("*foo")
{:error, {'nothing to repeat', 0}}