Authorize regexp in Plack::App::URLMap

[matjmat]

Hi,
I understand that we cannot currently use regexp in the path when mounting an application, mainly due to:

 push @{$self->{_mapping}}, [ $host, $location, qr/^\Q$location\E/, $app ];

in: Plack::App::URLMap

I would like to know:

• if there is a way to do it right now without modifying the code
• what is the rational behing using the \Q and avoiding regexp (i suspect something linked to security reasons)
• if it could be possible to add a $ENV parameter for authorizing the use of regexp in the map() something along:
  ``if ( $ENV{PLACK_URLMAP_ALLOWREGEX} ) {
  push @{$self->{_mapping}}, [ $host, $location, qr/^$location/, $app ];
  } else {
  push @{$self->{_mapping}}, [ $host, $location, qr/^\Q$location\E/, $app ];
  }
  (happy to provide a real patch if ok in the idea)

Best,
Mathieu