Modern Perl for the Unfrozen Paleolithic Perl Programmer discusses many changes to Perl and its ecosystem since 2001 when the caveman programmer fell into a glacier. Some key changes include Perl version 5.22, new language features like defined-or and subroutine signatures, and tools like Perlbrew, Plenv and cpanm. Modern web development uses Plack/PSGI instead of CGI.pm. The speaker recommends modules like JSON::MaybeXS, Moose/Moo and websites like CPAN Ratings, MetaCPAN and Perl Weekly to stay up-to-date.

1. Modern Perl for the
Unfrozen Paleolithic
Perl Programmer
John SJ Anderson ⭐ Infinity Interactive ⭐ @genehack
DC-Balmer Perl Workshop ⭐ 16 Apr 2016

2. Disclaimer
I'mma talk pretty fast. Feel free to ask questions particularly if I'm moving too quickly

3. I'M JUST A CAVEMAN
YOUR MODERN PERL
FRIGHTENS AND CONFUSES ME
I was inspired to give this talk by a few online friends who happen to be Perl programmers -- but they're not engaged with the community, they're just using Perl to get a
job done, and there's a widening gulf between what I think is reasonable and what they're doing -- so I wanted to put together sort of an info dump

4. Welcome
to 2016!
So, hi, unfrozen caveman Perl programmer! Welcome to 2016!

5. Quite a few
things have
changed...
Many things have changed since you fell into that glacier in 2001,

6. ...but
many
haven't

7. There's a Clinton
running for
President!
Perl6 is still just about going to be released!

8. We're still
using Perl5!
Most of us are still happily coding in Perl5, however

9. 2001:
Perl 5.6
When you slipped into that big hole in the ice, perl 5.6 was the latest and greatest

10. 2016:
Perl 5.22
But we're all the way up to 5.22 now

11. 2016:
Perl 5.22
4But we're all the way up to 5.22 now

12. Many
language
improvements

13. Unicode
support!
You probably don't remember Unicode -- it was around in 2001, but not terribly important or very well understood. It's way too complicated to get into here, just know
that now we can get _really_ expressive in our Perl code

14. 😀So it's much easier to tell if we're happy...

15. 💩... or when things aren't going quite as well.

16. This should be a familiar way of communication for you!

17. defined($this) ? $this : $that
defined-or
We got a great new feature in 5.10 called defined-or.
You've probably written code much like this hundreds of times.

18. $this // $that
defined-or
Now, we can just write this!
Which is pretty awesome. Defined-or was my favorite new perl feature of the 2000s

19. subroutine
signatures
Finally, we've also recently gotten support for subroutine signatures

20. sub add ($one, $two) {
return $one + $two;
}
so we don't even have to unpack @_ ourselves!
Who has started using subroutine signatures?

21. new tools
It's not just language level features, we also have a host of new tools to make it easier to work with Perl

22. "system" perl:
These days, we make a distinction between the Perl that comes with your OS

23. "system" perl:
just say no
and encourage people not to use it for their development projects

24. /usr/bin/perl
Yes, that means good old /usr/bin/perl...

25. /usr/bin/perl
is no more. Instead, we use tools to install new Perls, outside the control of the OS

26. perlbrew
The first tool that was developed for this purpose is called Perlbrew

27. perlbrew.pl
which you can get at perlbrew.pl

28. plenv
there's also a newer option, plenv

29. https://github.com/tokuhirom/plenv
it's website isn't quite as snazzy as perlbrew's

30. advantages
• Solves "vendor Perl lockin" issues
• Install multiple Perls in your home directory
• ... or elsewhere
• Trivially switch from Perl version to Perl version
• Able to install modules without special permissions
• Easy to stay up to date with Perl development
either one of these tools will give you numerous advantages over using the system perl

31. plenv > perlbrew
• Less magic messing around with PATH
• Can "pin" Perl different ways: globally, per-shell, or
per-directory
personally, i'm using plenv these days -- the ability to easily specify a Perl version for a particular project is particularly useful to me

32. perlbrew > plenv
• Kickass website

33. speaking of installing in
your $HOME…

34. local::lib

35. local::lib
• Install your own copies of modules
• In your $HOME (so no special permissions needed)
• Can also install per-project modules
• Integrates well with other tools

36. speaking of installing stuff…

37. cpanminus
cpanm
We've got a new CPAN client these days

38. % cpan Git::Wrapper
CPAN: Storable loaded ok (v2.54)
Reading '/Users/genehack/.cpan/Metadata'
Database was generated on Sat, 10 Oct 2015 01:17:02 GMT
Running install for module 'Git::Wrapper'
CPAN: LWP::UserAgent loaded ok (v6.13)
Fetching with LWP:
http://cpan.schatt.com/authors/id/G/GE/GENEHACK/Git-Wrapper-0.045.tar.gz
CPAN: YAML loaded ok (v1.15)
CPAN: Digest::SHA loaded ok (v5.95)
Fetching with LWP:
http://cpan.schatt.com/authors/id/G/GE/GENEHACK/CHECKSUMS
CPAN: Compress::Zlib loaded ok (v2.068)
Checksum for /Users/genehack/.cpan/sources/authors/id/G/GE/GENEHACK/Git-
Wrapper-0.045.tar.gz ok
tmp-47326 for tmp-47326: No such file or directory at /opt/plenv/versions/5.23.2/lib/
perl5/5.23.2/CPAN/Distribution
.pm line 468.
CPAN: File::Temp loaded ok (v0.2304)
CPAN: CPAN::Meta::Requirements loaded ok (v2.133)
CPAN: Parse::CPAN::Meta loaded ok (v1.4417)
CPAN: CPAN::Meta loaded ok (v2.150005)
CPAN: Module::CoreList loaded ok (v5.20150820)
Configuring G/GE/GENEHACK/Git-Wrapper-0.045.tar.gz with Makefile.PL
Locating bin:git... found at /opt/git/bin/git.
Checking if your kit is complete...
Looks good
Generating a Unix-style Makefile
Writing Makefile for Git::Wrapper
Writing MYMETA.yml and MYMETA.json
this is the output from using the default 'cpan' client to install something.

39. GENEHACK/Git-Wrapper-0.045.tar.gz
[17/1516]
/opt/plenv/versions/5.23.2/bin/perl5.23.2 Makefile.PL -- OK
Running make for G/GE/GENEHACK/Git-Wrapper-0.045.tar.gz
cp lib/Git/Wrapper/File/RawModification.pm blib/lib/Git/Wrapper/File/RawModification.pm
cp lib/Git/Wrapper.pm blib/lib/Git/Wrapper.pm
cp lib/Git/Wrapper/Statuses.pm blib/lib/Git/Wrapper/Statuses.pm
cp lib/Git/Wrapper/Exception.pm blib/lib/Git/Wrapper/Exception.pm
cp lib/Git/Wrapper/Log.pm blib/lib/Git/Wrapper/Log.pm
cp lib/Git/Wrapper/Status.pm blib/lib/Git/Wrapper/Status.pm
Manifying 6 pod documents
GENEHACK/Git-Wrapper-0.045.tar.gz
/usr/bin/make -- OK
Running make test
PERL_DL_NONLAZY=1 "/opt/plenv/versions/5.23.2/bin/perl5.23.2" "-MExtUtils::Command::MM" "-
MTest::Harness" "-e" "und
ef *Test::Harness::Switches; test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/00-load.t ............... 1/6 # Testing Git::Wrapper 0.045
t/00-load.t ............... ok
t/author-err.t ............ skipped: these tests are for testing by the author
t/basic.t ................. # Testing git version: 2.5.2
t/basic.t ................. ok
t/git_binary.t ............ ok
t/parse_args.t ............ ok
t/path_class.t ............ # Testing git version: 2.5.2
t/path_class.t ............ ok
t/release-pod-coverage.t .. skipped: these tests are for release candidate testing
t/release-pod-syntax.t .... skipped: these tests are for release candidate testing
All tests successful.
Files=8, Tests=67, 1 wallclock secs ( 0.04 usr 0.02 sys + 0.39 cusr 0.31 csys = 0.76 CPU)
Result: PASS
GENEHACK/Git-Wrapper-0.045.tar.gz
and this is more of the output...

40. (still not done
but I got tired
of pasting.)

41. % cpanm Git::Wrapper
--> Working on Git::Wrapper
Fetching http://www.cpan.org/authors/id/G/GE/GENEHACK/Git-Wrapper-0.045.tar.gz ... OK
Configuring Git-Wrapper-0.045 ... OK
Building and testing Git-Wrapper-0.045 ... OK
Successfully installed Git-Wrapper-0.045
this is the output from cpanm installing the same thing

42. speaking of stuff on CPAN…

43. https://metacpan.org/
we have a whole new website for interacting with CPAN

44. search.cpan.org
search.cpan.org is still around...

45. https://metacpan.org/
but metacpan integrates and visualizes a bunch of information in a really useful way

46. https://metacpan.org/
things like a syntax-highlighted source view, linking to home pages and code repos, showing test results, and the amount of activity in a project

47. https://github.com/CPAN-API/metacpan-web
it's also open source, so if you can think of a way to make it better, you can

48. Duck Duck Go
we also have a new search engine here in 2016. it's cool, and it's partially written in Perl

49. Duck Duck Go
!cpanm
The most useful feature, though, is ability to use 'bang searches' to restrict your search to a particular site - this is how you search metacpan

50. speaking of modules...
if you haven't been playing close attention (and since you were frozen, you haven't been!) there are a few new modules you may have missed

51. JSON::MaybeXS
anybody doing web development these days needs to interact with JSON - using JSON::MaybeXS will make sure that you have a JSON library available, picking the best
one from a number of alternatives

52. Moose
Moo
To get a handle on how we do OOP in Perl these days, you should look into Moose -- and then when you're ready to write some code, you'll probably be able to get
away with dropping down to Moo

53. CGI.pm
is
gone
I do have some bad news for you -- CGI.pm has been pulled out of core

54. (not really)
don't worry, you can still find it on CPAN

55. Plack
But the current standard for web development in Perl is Plack/PSGI. Offers a number of advantages over CGI, and is the basis for all modern Perl web frameworks

56. speaking of Perl websites…
we have quite a few new websites these days, which make it easier to keep up with the current state of things

57. http://cpanratings.perl.org/
one of the problems with cpan is there's just _so_ _much_ _stuff_ there. it can be hard to decide which one of a dozen different modules to use. cpanratings helps with
this problem

58. http://cpanratings.perl.org/
you can see individual reviews, which version they're reviewing, and so on.

59. https://metacpan.org/
MetaCPAN links to reviews as well as showing an average review score

60. http://cpants.cpanauthors.org/
we also have CPANTS - automated testing of some best practices around module development

61. http://cpants.cpanauthors.org/
here's what that looks like for a particular module. super useful if you're not sure you're doing things the "right" way

62. https://metacpan.org/
MetaCPAN links to CPANTS too

63. http://prepan.org/
We also have PrePAN, which is a place to get feedback on module ideas you haven't even written yet

64. speaking of staying up to
date on Perl news…
we also have some sites that make it easier to keep up to date with what's going on in the perl world

65. http://perlweekly.com/
there's perl weekly, which is a once a week email newsletter aggregating perl related news from all over the web

66. http://blogs.perl.org/users/sawyer_x/
and in a recent development, sawyer has revived the p5p weekly email summary -- excellent if you want to keep up with what's going on with perl5 development but
don't have time to follow the email list yourself

67. thanks!

68. questions?