method set( :$x = $.x, :$y = $.y )

##</code><code>##

Named parameters

In contrast to positional parameters, named parameters are referred

by their names.  The following function takes two parameters called 

$from and $to:

sub distance(:$from, :$to) { $from - $to }

Now, to call the function, you need to name the arguments:

say distance(from => 30, to => 10); # 20

It is an error to pass the arguments as if they were positional.
For example, a call distance(30, 10) generates an error: ...

##</code><code>##

class Rectangle {
    has Int $.length = 1;
    has Int $.width = 1;
 
    method area(--> Int) {
        return $!length * $!width;
    }
}
 
my $r1 = Rectangle.new(length => 2, width => 3);
say $r1.area();

##</code><code>##

has Bool $.done;

##</code><code>##

has Bool $!done;
method done() { return $!done }

##</code><code>##

use v6;

class Point {
    has $.x = 0;
    has $.y = 0;

    method gist { "[$.x, $.y]" }

    method set( :$joe = $!x, :$susan = $!y ) { 
        $!x = $joe; 
        $!y = $susan;
    }
}

my $point = Point.new();
say $point.x;   # 0
say $point;    # [0, 0]
# $point.x = 3;  Error!

$point = Point.new(x => 3, y => 5);
say $point;  # [3,5]

$point.set(joe => 10, susan => 20);
say $point;  # [10, 20]

$point.set(joe => 100);
say $point;  # [100, 20]