NAME 
src/builtins/named-unary.pir - Perl6 named unary builtins
Functions
- HOW($x)
- WHAT($x)
- Return the metaclass or protoobject for
$x. - defined($x)
- Returns a true value if $x is defined, and a false value otherwise.
- undefine $x
- Sets $x to an undefined value
- rand($x)
- Returns a random floating point number greater than or equal to zero and less than $x.
