“There are a huge number of books out there about Perl. A quick
search on Amazon reveals 362 books; allowing for false positives
and books where Perl is a minor part, I’d conservatively estimate
there to be over 250 books primarily on Perl on the market at the
moment. Are they any good? … If you want to make sure you’re
learning high-class Perl, you need something external and
objective. So, let’s have a look at a few criteria that you can use
to evaluate Perl books yourself; this is basically how I’d go about
stress-testing a new book when I got hold of it.”
“Who’s the author? …check out CPAN; you can search for the
author’s CPAN directory at http://search.cpan.org and see what
they’ve submitted, if anything. If they’ve got a directory on CPAN,
then you can download their code and have a look at it. Is it
documented? Is the documentation clear and easy to read? Does the
code pass the other tests here?”
“use strict and warnings… In Perl 5.6.0 and later, the
warnings system is controlled by the words use warnings; in
previous versions of Perl, -w should appear on the first line of a
program, usually after something resembling #!/usr/bin/perl. If the
author isn’t encouraging you to use warnings — if you don’t see a
-w on the top line of examples of full programs, or a use warnings
somewhere near the top of the code — put the book down.
Forcefully. …look for the words ‘use strict’ around the beginning
of the examples. Some elements of strict are concerned with
variable use and scoping, which may not be discussed until quite
late in the book depending on how the author’s chosen to lay it
out, so don’t worry if you don’t see use strict in the first few
chapters.”