I figured since my version of Modern::Perl (1.03) came with my version of Perl (5.12.5)...

It's not a core module, so someone bundled it with your version of Perl. Unfortunately, the bundled version predates the year specifier. Upgrading to the most recent Modern::Perl version will let you use a year specifier (and it will be quick and easy).

(After reading M/Perl.pm, I see the validity of year specifier (as version specifier).) chromatic, why have both the regular version string and also (plain) year as version?

Whomever built "(your) version of Perl (5.12.5)", might have included the older version. M::P does not come along with perl 5.16.3; it is also missing from 5.12.5 per module list. FWIW, current version is 1.20121103 on CPAN; also, no "2011" version is listed there.

Greetings chromatic, and thank you for your thoughtful reply, and the great book!
Indeed. The version added to my packaged Perl, was added. Sorry for the incorrect assumption.
As to the "2011"; as I read the book on page i. I see the following (quoted literally):

Running Modern Perl
The Modern::Perl...

#!/usr/bin/env perl
use Modern::Perl 2011;
use autodie;
. . . which is equivalent to:
#!/usr/bin/env perl
use 5.012;
use warnings;
use autodie;
[download]

Note the "2011".

I blindly copied the

use Modern::Perl 2011;
[download]

into a simple Perl script. Which resulted in the error I quoted in the title of this thread.
It seems clear to me at this point
1) I need to upgrade my version of Modern::Perl
2) I should simply disregard the "2011" in the use statement above

Thanks again for taking the time to respond, and for sharing your book so freely.

--Chris



#!/usr/bin/perl -Tw
use perl::always;
my $perl_version = (5.12.5);
print $perl_version;