Perl 6 Deep Dive

Slurpy parameters

The great part of Perl 6 is that it allows passing arrays and hashes in function signatures, Meaning that an array is passed as a single value, not as a list of its values. Consider the following simple example of how the add function can be modified to return the sum of all the elements of an array:

sub add(@arr) {
    [+] @arr
}

my @a = <10 20 30>;
say add(@a); # 60

The [+] construction is a reduced form of the + operator; see the details in Chapter 4, Working with Operators. It returns the sum of all the elements of the @arr array, which is the only argument of the sub.

You may safely add more arguments after the array to the sub. Let's create a function to calculate the sum of the first $n elements of an array:

sub sum_first(@a, ...