Kernel.or
You're seeing just the macro
or, go back to Kernel module for more information.
Strictly boolean "or" operator.
If left is true, returns true; otherwise returns right.
Requires only the left operand to be a boolean since it short-circuits.
If the left operand is not a boolean, a BadBooleanError exception is
raised.
Allowed in guard tests.
Examples
iex> true or false
true
iex> false or 42
42
iex> 42 or false
** (BadBooleanError) expected a boolean on left-side of "or", got: 42