use strict;

# The variable $post contains the text to check.
# $, -> and => are searched for.

my $perlisms = 0;
my $perlisms_limit = 3;

for ( split /\n/, $post ) {
        $perlisms += s/\$|->|\=>//g;
        
        if ( m/<code>/ ) {
                $perlisms = 0;
                last;
        }
}

print "Warning text goes here."
if $perlisms >= $perlisms_limit;