1brc attempt in Raku

1brc.raku

#!/usr/bin/env raku

sub generate-stats($path) {
    my $c = Channel.new;
    $c.send($_) for $path.IO.lines()
                            .race(batch => 1024)
                            .map({ my @v = .split(";");
                                   @v; });
    $c.close;

    my %h;
    my $i = 0;
    
    for $c.list -> ($country, $measurement) {

        if %h{$country}:exists {
            my ($min, $avg, $max, $count) = %h{$country};
            
            if $measurement < $min {
                $min = $measurement;
            }

            if $measurement > $max {
                $max = $measurement;
            }

            $count++;

            # Incrementally calculating new average.
            # https://blog.demofox.org/2016/08/23/incremental-averaging/

            $avg += ($measurement - $avg) / $count;

            %h{$country} = [$min, $avg, $max, $count]        
        } else {
            %h{$country} = [$measurement, $measurement, $measurement, 1]
        }

        $i++;

        if $i %% 10_000 {
            say "Processed $i rows."
        }
    }
    say %h;
}


sub MAIN($file) {
    my $path = IO::Path.new($file);

    generate-stats($path);
}