It's also possible to use multiple "capturing lookaheads" for a kind of logical-and effect:

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'xx foo yy bar zz baz';
 ;;
 if (my ($c1, $c2, $c3) = $s =~ m{
   \A  (?! .* zot)  (?= .* (bar))  (?= .* (baz))  (?= .* (foo))
   }xms
   ) {
   print qq{c1 '$c1'  c2 '$c2'  c3 '$c3'};
   }
"
c1 'bar'  c2 'baz'  c3 'foo'
[download]

Update: Another trick I like is to capture match success separately for later use, e.g., in conditionals:

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'xx foo yy bar zz baz';
 ;;
 my $match = my ($c1, $c2, $c3) = $s =~ m{
   \A  (?! .* zot)  (?= .* (bar))  (?= .* (baz))  (?= .* (foo))
   }xms;
 ;;
 if ($match) {
   print qq{c1 '$c1'  c2 '$c2'  c3 '$c3'};
   }
 else {
   print 'no match';
   }
"
c1 'bar'  c2 'baz'  c3 'foo'
[download]

Later Update: Oops... I didn't read beyond the first two  $x+2 subscripts to realize the matches might be made against completely different variables; shoulda read choroba's reply more carefully. Oh well, the trick still works with a single variable.