slowlog.p6

use v6;

class L {
    method log($l, $s) { say "$l: $s" };
    method FALLBACK($name, $s) {
        my $c_name = $name;
        if ($name ~~ / log (\d) /) {
            my $level = $0;
            self.^add_method($name, method (Str $msg) {
                self.log($level, $msg)
            });
            self.^compose();
            self."log$level"($s)
        }
    }
};

my $log = L.new;
$log.log0("foo");
$log.log1("bar");