Passing named arrays as command line arguments in Raku

Raku provides a MAIN method that, when present, can define the arguments the application expects. This is very useful, because it allows for argument checking and definition. However, while passing simple positional arguments to a MAIN is simple, when dealing with named arrays you have to repeat the positional name for every single element. As an example, assume we have written the following simple application:

sub MAIN( :@books, :@years )
{
    say "Luca Ferrari has written the following books:";
    for ( @books [Z] @years ) {
		say "- $_[0] ( $_[1] )";
    }
}

In order to define the @books and @years you have to specify the options --books and --names respectively on the command line. And you have to repeat them every time you need to append a new element to the array. The beauty part is that you don’t have to place all the arguments grouped, but you can mix arguments and Raku will deal them! In other words, the following two invocations are equivalent:



and in both cases the output will be: