Array concatenation

# the prefix:<|> operator (called "slip") can be used to interpolate arrays into a list:
sub cat-arrays(@a, @b) { 
    |@a, |@b 
}

my @a1 = (1,2,3);
my @a2 = (2,3,4);
cat-arrays(@a1,@a2).join(", ").say;

Output:

1, 2, 3, 2, 3, 4