my $p = Parse::RecDescent->new( <<'END_GRAMMAR' );

      parse: item(s)         { "<ROOT>" . join("", @{$item[1]}) . "</ROOT>" }
       item: /\w+/ /\([^\)]+\)=/ data
                             { "<$item[1]>$item[3]</$item[1]>" }
       data: aggregate | string | integer
  aggregate: "(" item(s) ")" { join "", @{$item[2]} }
     string: /'([^']*)'/     { $1 }
    integer: /\d+/           { $item[1] }
END_GRAMMAR

undef $/;
print $p->parse(<DATA>);