gistfile1.txt

            when Supply {
                $fragment ~~ s:i{^ "row=" } = "" and self.rowrange ($fragment);
                my int $i = 0;
               #@in = gather while ($in.tap) -> $r { !$!rrange || $!rrange.in ($i++) and take $r };
                @in = gather {
                    $in.act: {
                        ("Act ", $_).say;
                        !$!rrange || $!rrange.in ($i++) and take $_;
                        }
                   #$in.wait;
                    };
                @in.perl.say;
                }


=>

Act  foo,bar,baz
[]<>