I like that. Trying to come up with a map() version, but

my $scratch = '';
my @a = (map(defined() ? ($scratch.=$_)[()]
                       : substr($scratch,0,length($scratch),''),
             split /(\\.)|X/, $escaped_str),
         length($scratch) ? $scratch : ());
[download]

is the best I can do. And that's way too ugly.

Maybe something based on @a = @{List::Util::reduce { ... } [], split... };