>perl -wMstrict -le
"my $left_text  = [ qw{ when rome romans} ];
 my $right_text = 'When in Rome, do as the Romans.';
 my $regex = qr{ @{[ join '|', @$left_text ]} }xmsi;
 my $found =()= $right_text =~ m/$regex/xmsg;
 print qq{found == $found};
"
found == 3