You could simply:
#!/usr/bin/perl -w
use strict; # Every job should
# Start of comments
if (defined undef) {
foo...
}
# End of comments
&do_more_stuff();
In terms of efficency - using a constant should kill a large block like that at compile time as opposed to run time (although the optimiser might take away the code in the solution above?).
#!/usr/bin/perl -w
use strict;
use constant COMMENT_WRAPPER => 0;
# Start comments
if (COMMENT_WRAPPER) {
Blah Blah
}
# End comments
&carry_on_with_stuff();
game(Wookie,opponent) eq 'Wookie' ? undef $problem : remove_limbs(arms,opponent);