do{

    # read the input
    print "Type a word or phrase: ";
    $line = <>;
    
    # strip out stuff that would disturb the palindrome comparison
    # and convert to lowercase...
    $line =~ s/\W//g; # removes space and nonalphanumerics        
    $line =~ tr/A-Z/a-z/;  # converts to lowercase. Better: lc($line) !

    # get the list of letter and reverse it
    @letters = split //, $line;
    $reverse = join "", reverse @letters;
    
    # a palindrome is equal to its reverse or a one letter word.
    if(@letters == 0){
    print "End of session\n";
    }
    elsif(@letters == 1){
    print "One letter palindrome, trivial!\n";
    }
    elsif($reverse eq $line){
    print "This is a palindrome.\n";
    }
    else{
    print "Not a palindrome.\n";
    }
}while($line);

#!/usr/bin/perl

test();

sub isPalindrome {
    my($line) = shift;

    # strip out stuff that would disturb the palindrome comparison
    # and convert to lowercase...
    $line =~ s/\W//g; # removes space and nonalphanumerics        
    $line =~ tr/A-Z/a-z/;  # converts to lowercase. Better: lc($line) !

    # get the list of letter and reverse it
    @letters = split //, $line;
    $reverse = join "", reverse @letters;
    
    return ($reverse eq $line);
}

sub displayPalindromeResults {
    my($line) = shift;
    
    print $line;
    
    my($lineLen) = length($line);
    
    if ($lineLen==0) {
        print "End of session\n";
    } elsif($lineLen==1) {
        print " is a one letter palindrome, trivial!\n";
    } elsif(isPalindrome($line)) {
        print " is a palindrome.\n";
    } else {
        print " in NOT a palindrome.\n";
    }
}

sub userInput {
    do{
        # read the input
        print "Type a word or phrase: ";
        $line = <>;
        displayPalindromeResults($line);
    } while($line);
}

sub test {
    displayPalindromeResults("a");
    displayPalindromeResults("foo");
    displayPalindromeResults("mom");
}