has $.foo;            # public attribute
has $:bar;            # private attribute
method foo (){...}    # public method
method :bar () {...}  # private method
...
$self.foo()           # always calls public method virtually
     .foo()           # unary variant
$self.:bar()          # always calls private method
     .:bar()          # unary variant
...
$self.bar()           # calls public bar, not private.