Each module gets an __info__/1 function when it’s compiled. The function takes
one of the following atoms:
:functions- keyword list of public functions along with their arities:macros- keyword list of public macros along with their arities
For example, we can list the Kernel module’s functions:
iex> Kernel.__info__ :functions
[!=: 2, !==: 2, *: 2, +: 1, +: 2, ++: 2, -: 1, -: 2, --: 2, /: 2, <: 2, <=: 2,
==: 2, ===: 2, =~: 2, >: 2, >=: 2, abs: 1, apply: 2, apply: 3, binary_part: 3,
bit_size: 1, byte_size: 1, div: 2, elem: 2, exit: 1, function_exported?: 3,
get_and_update_in: 3, get_in: 2, hd: 1, inspect: 1, inspect: 2, is_atom: 1,
is_binary: 1, is_bitstring: 1, is_boolean: 1, is_float: 1, is_function: 1,
is_function: 2, is_integer: 1, is_list: 1, is_map: 1, is_number: 1, is_pid: 1,
is_port: 1, is_reference: 1, is_tuple: 1, length: 1, macro_exported?: 3,
make_ref: 0, ...]