Modern Perl for the Unfrozen Paleolithic

Perl ProgrammerJohn SJ Anderson ⭐ Infinity Interactive ⭐ @genehack

DC-Balmer Perl Workshop ⭐ 16 Apr 2016

Disclaimer

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

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

Welcome to 2016!

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

Quite a few things have changed...

Many things have changed since you fell into that glacier in 2001,

...but many

haven't

There's a Clinton running for President!

Perl6 is still just about going to be released!

We're still using Perl5!

Most of us are still happily coding in Perl5, however

2001: Perl 5.6

When you slipped into that big hole in the ice, perl 5.6 was the latest and greatest

2016: Perl 5.22

But we're all the way up to 5.22 now

2016: Perl 5.224

But we're all the way up to 5.22 now

Many language

improvements

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

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

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

This should be a familiar way of communication for you!

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.

$this//$that

defined-or

Now, we can just write this!

Which is pretty awesome. Defined-or was my favorite new perl feature of the 2000s

subroutine signatures

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

subadd($one,$two){return$one+$two;}

so we don't even have to unpack @_ ourselves!

Who has started using subroutine signatures?

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

"system" perl:

These days, we make a distinction between the Perl that comes with your OS

"system" perl: just say no

and encourage people not to use it for their development projects

/usr/bin/perl

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

/usr/bin/perl

is no more. Instead, we use tools to install new Perls, outside the control of the OS

perlbrewThe first tool that was developed for this purpose is called Perlbrew

perlbrew.plwhich you can get at perlbrew.pl

plenvthere's also a newer option, plenv

https://github.com/tokuhirom/plenv

it's website isn't quite as snazzy as perlbrew's

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

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

perlbrew > plenv• Kickass website

speaking of installing in your $HOME…

local::lib

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

speaking of installing stuff…

cpanminus

cpanmWe've got a new CPAN client these days

%cpanGit::WrapperCPAN:Storableloadedok(v2.54)Reading'/Users/genehack/.cpan/Metadata'DatabasewasgeneratedonSat,10Oct201501:17:02GMTRunninginstallformodule'Git::Wrapper'CPAN:LWP::UserAgentloadedok(v6.13)FetchingwithLWP:http://cpan.schatt.com/authors/id/G/GE/GENEHACK/Git-Wrapper-0.045.tar.gzCPAN:YAMLloadedok(v1.15)CPAN:Digest::SHAloadedok(v5.95)FetchingwithLWP:http://cpan.schatt.com/authors/id/G/GE/GENEHACK/CHECKSUMSCPAN:Compress::Zlibloadedok(v2.068)Checksumfor/Users/genehack/.cpan/sources/authors/id/G/GE/GENEHACK/Git-Wrapper-0.045.tar.gzoktmp-47326fortmp-47326:Nosuchfileordirectoryat/opt/plenv/versions/5.23.2/lib/perl5/5.23.2/CPAN/Distribution.pmline468.CPAN:File::Temploadedok(v0.2304)CPAN:CPAN::Meta::Requirementsloadedok(v2.133)CPAN:Parse::CPAN::Metaloadedok(v1.4417)CPAN:CPAN::Metaloadedok(v2.150005)CPAN:Module::CoreListloadedok(v5.20150820)ConfiguringG/GE/GENEHACK/Git-Wrapper-0.045.tar.gzwithMakefile.PLLocatingbin:git...foundat/opt/git/bin/git.Checkingifyourkitiscomplete...LooksgoodGeneratingaUnix-styleMakefileWritingMakefileforGit::WrapperWritingMYMETA.ymlandMYMETA.json

this is the output from using the default 'cpan' client to install something.

GENEHACK/Git-Wrapper-0.045.tar.gz[17/1516]/opt/plenv/versions/5.23.2/bin/perl5.23.2Makefile.PL--OKRunningmakeforG/GE/GENEHACK/Git-Wrapper-0.045.tar.gzcplib/Git/Wrapper/File/RawModification.pmblib/lib/Git/Wrapper/File/RawModification.pmcplib/Git/Wrapper.pmblib/lib/Git/Wrapper.pmcplib/Git/Wrapper/Statuses.pmblib/lib/Git/Wrapper/Statuses.pmcplib/Git/Wrapper/Exception.pmblib/lib/Git/Wrapper/Exception.pmcplib/Git/Wrapper/Log.pmblib/lib/Git/Wrapper/Log.pmcplib/Git/Wrapper/Status.pmblib/lib/Git/Wrapper/Status.pmManifying6poddocumentsGENEHACK/Git-Wrapper-0.045.tar.gz/usr/bin/make--OKRunningmaketestPERL_DL_NONLAZY=1"/opt/plenv/versions/5.23.2/bin/perl5.23.2""-MExtUtils::Command::MM""-MTest::Harness""-e""undef*Test::Harness::Switches;test_harness(0,'blib/lib','blib/arch')"t/*.tt/00-load.t...............1/6#TestingGit::Wrapper0.045t/00-load.t...............okt/author-err.t............skipped:thesetestsarefortestingbytheauthort/basic.t.................#Testinggitversion:2.5.2t/basic.t.................okt/git_binary.t............okt/parse_args.t............okt/path_class.t............#Testinggitversion:2.5.2t/path_class.t............okt/release-pod-coverage.t..skipped:thesetestsareforreleasecandidatetestingt/release-pod-syntax.t....skipped:thesetestsareforreleasecandidatetestingAlltestssuccessful.Files=8,Tests=67,1wallclocksecs(0.04usr0.02sys+0.39cusr0.31csys=0.76CPU)Result:PASSGENEHACK/Git-Wrapper-0.045.tar.gz

and this is more of the output...

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

%cpanmGit::Wrapper-->WorkingonGit::WrapperFetchinghttp://www.cpan.org/authors/id/G/GE/GENEHACK/Git-Wrapper-0.045.tar.gz...OKConfiguringGit-Wrapper-0.045...OKBuildingandtestingGit-Wrapper-0.045...OKSuccessfullyinstalledGit-Wrapper-0.045

this is the output from cpanm installing the same thing

speaking of stuff on CPAN…

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

search.cpan.orgsearch.cpan.org is still around...

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

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

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

Duck Duck Go

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

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

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

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

MooseMoo

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

CGI.pm is

gone

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

(not really)

don't worry, you can still find it on CPAN

PlackBut 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

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

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

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

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

http://cpants.cpanauthors.org/

we also have CPANTS - automated testing of some best practices around module development

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

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

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

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

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

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

thanks!

questions?