Perl Debugged

8.2. A Menagerie of Typos

At this point, we're going to go on a tour of typo examples with different diagnoses.

8.2.1. Quotable Quotes

Our first program sets up a hash %quotation indexed by author and then goes on:

while (my ($author, $quote) = each %quotation)
   {
   print 'Quote of the Day: "$quote" by $author\n';
   }

This runs, but takes us too literally:

Quote of the Day: "$quote" by $author\nQuote of the Day:
"$quote" by $author\nQuote of the Day: "$quote" by $author\n...

Aha! Nothing is being interpolated because we're using single quotes. We change them to double quotes:

3  while (my ($author, $quote) = each %quotation)
4     {
5     print "Quote of the Day: "$quote" by $author\n";
6     }

Yikes, now we get three errors:

 Scalar found where operator ...