>perl -wMstrict -le
"sub rx (&$) {
   my $c_regex = shift;
   local $_ = shift;
   $c_regex->();
   return $_;
   }
 ;;
 my $s = 'a b c';
 print rx { s/ /_/g } $s;
 ;;
 my @ra = 'p q r';
 print rx { s/ /_/g } @ra;
"
a_b_c
1

>perl -wMstrict -le
"sub rx (&@) {
   my $c_regex = shift;
   local $_ = shift;
   $c_regex->();
   return $_;
   }
 ;;
 my $s = 'a b c';
 print rx { s/ /_/g } $s;
 ;;
 my @ra = 'p q r';
 print rx { s/ /_/g } @ra;
"
a_b_c
p_q_r