! (for failable initializers), A failable Town initializer
! (forced unwrap) operator, Optional Types
, Modifying an Optional in Place
! (implicitly unwrapped optional), Implicitly Unwrapped Optionals
! (logical not) operator, if/else
!= (not equal to) operator, if/else
, Buy one method, get another free!
!== (nonidentity) operator, if/else
$0, $1... (shorthand argument names), Closure Expression Syntax
% (remainder) operator, Integer division
%= (remainder assignment) operator, Operator shorthand
& (for arguments passed to in-out parameters), In-out parameters
& (for protocol composition), Protocol Composition
&& (logical and) operator, if/else
&* (overflow multiplication) operator, ...