#! perl
# 1134136.pl
use strict;
my ($bottom, $top);
my @mountain = ($bottom, $top, foo);
exit;

##</code><code>##

[05:38][nick:~/monks]$ perl 1134136.pl
Bareword "foo" not allowed while "strict subs" in use at 1134136.pl line 4.
Execution of 1134136.pl aborted due to compilation errors.

##</code><code>##

#! perl 
# 1134136-2.pl
use warnings;
my ($bottom, $top);
my @mountain = ($bottom, $top, foo);
exit;

##</code><code>##

[05:41][nick:~/monks]$ perl 1134136-2.pl
Unquoted string "foo" may clash with future reserved word at 1134136-2.pl line 5.