You may use (?{ code }), with the perlre-warning in mind:
WARNING: This extended regular expression fea­ ture is considered highly experimental, and may be changed or deleted without notice.

An example:

#!/usr/bin/perl
package Test;

sub test {
    return 'test_1';
}

package main;
if ( 'test_1' =~ m/(?{ Test::test() })/) {
    print "ok\n";
} else {
    print "not ok\n";
}
__END__
ok
[download]

regards,
tomte

Hlade's Law:

If you have a difficult task, give it to a lazy person --
they will find an easier way to do it.

sub word { '( \w+ )' }

print "Hello World" =~ /${\ main->word }/x;

__output__

Hello
[download]

_________
broquaint

You could always assign the return value of the object method to a variable, then attempt to match that variable:

my $value = C->flag();

if (m/$value/} { print "OK" }
else { print "Not OK" }
[download]

Hope that helps,
-- Foxcub
A friend is someone who can see straight through you, yet still enjoy the view. (Anon)

$_ =~ C->flag();
[download]

sub flag {
  return '(.)foo(\\d+)bar'
}
[download]

#--- complex.pm
package complex;
use strict;

sub whatis{
    my $self = shift;
    my $input = shift;
    my %data = (
    ip_address => \qr/\d+\.\d+\.\d+\.\d+/,
    phone => \qr/^\d{3}[-]\d{3}[-]\d{4}$/,
    );

    foreach(keys %data){
        return $data{$_} if /$input/;
    }
    return 0;
}
1;
#--- test.pl
#!/perl/bin/perl
use complex;
use strict;

my @list1 = qw ( 704-123-4569 
        115.43.2.123 
        112.32.24.2 
    );

push @list1, "312-231-2312 (ext. 23)";


my @list2 = qw ( ip_address phone );


foreach (@list1){
  foreach my $x (@list2){
    if ( /${complex->whatis($x)}/ ){
    print "$_ is an $x\n";
     }
  }

  if ( /${complex->whatis('phone')}*\s+\(ext\. (\d+)\)/ ){
        print "$_ is an phone with ext $1 \n";
  }
}
[download]

package C;

my $consts = { CONST1 => 1,
               CONST2 => 2,
               CONST3 => 3,
               CONST4 => 4,
                . . . 
             };
use overload '``' => sub { return $const_values{shift} } ;

# All constants can be accessed as by using AUTOLOAD
sub AUTOLOAD {
    no strict 'refs', 'subs';
    if ($AUTOLOAD =~ /.*::([A-Z]\w+)$/) {
      my $const_name = $1;
      *{$AUTOLOAD} = sub {return $const_values{$const_name}};
        return $const_values{$const_name};
    }
    return undef;
}
 
1;
[download]

if($status == C->CONST1) { print "1" }
elsif($status =~ /(2|3)/ { print "2 or 3" }
else                     { print 'Something' }
[download]

if($status == C->CONST1) { print "1" }
elsif($status =~ /(C->CONST2|C->CONST3)/ { print "2 or 3" }
else                     { print 'Something' }
[download]

$status == C->CONST3 or $status == C->CONST3
[download]

      
--------------------------------
SV* sv_bless(SV* sv, HV* stash);

As far as I read perlre, (?{}) is the only way to get code directly into a regexp.

so your wanted code must look like:

if ($status == C->CONST1)  {
     print "1" 
} elsif ($status =~ /(?{ C->CONST2 })|(?{ C->CONST3 })/) {
    print "2 or 3" ;
}
else {
    print 'Something';
}
[download]

I don't see, why you don't want to use some of the more readable solutions suggested by the other monks, espacially a sub that assembles the regexp for you seems a good way to me, though...
maybe that I really don't understand what you want to do...

regards,
tomte

---

Hlade's Law:

If you have a difficult task, give it to a lazy person --
they will find an easier way to do it.

Many thanks brothers, especially broquaint - excellent trick!!! ++++++++++++++++++++++++