use re 'eval';

my $string = qr[
      " [^"\\]* (?:\\.|[^"\\])* "
    | ' [^'\\]* (?:\\.|[^'\\])* '
]x;

my $alist = qr[(?: [^"'>]* | $string )*]x;
my $ehead = qr[ <\w+ $alist /? > ]x;

my $textarea = qr[
    <textarea $alist>
    (?:
          [^<]*
        | < (?!/textarea>)
    )*
    </textarea>
]x;

my $asp = qr[
    <%
    (?:
          (?> [^%"']* )
        | $string
        | % (?! > )
    )+
    %>
]x;

my $html = qr[
    (?:
          (?> [^<"'] )
        | $textarea
        | $ehead
        | </\w+>
    )+
]x;

my @parsed;
() = $string =~ /
          ($asp)  (?{ push @parsed, [asp  => $1] })
        | ($html) (?{ push @parsed, [html => $2] })
/gx;