Perl for newbies

I've heard the tutorials at Perl-Begin.org are a good way to get started with perl. Current, modern perl. Not some 15-year-old script kiddie intro.

Speaking of, it might be interesting to make a learnperlthehardway book, ala Write your own LxTHW and the companion site LearnCodeTheHardWay.org.

Homework!

It's been a long time since I've had schoolwork. Some habits die hard -- here I am 1 week in and rushing/procrastinating/just-plain-late with my first assignments!

I'm taking two courses at Stanford this fall. Maybe you know someone else in one of them? There are one hundred thousand people in my AI class. 100,000. Even our largest freshman intro courses at Caltech had fewer than 215 people, so this is three decimal orders of magnitude larger. Wow. I'm not sure how many people are signed up for the Machine Learning class, but it's probably similarly large.

Back to work!

Author dependencies in Dist::Zilla

Wanna edit/tweak/build/play-with a Dist::Zilla based perl module you've checked out? Seems daunting because "the module installer isn't included" or "what if I don't have the same helper modules that the author uses?" ? Worry Not!

It's easy to get the minimal pieces installed, so let's get to it.

Basic steps for building/using a Dist::Zilla based module from raw source:

1. Check out module source
2. install Dist::Zilla:
   cpanm Dist::Zilla
3. install author deps:
   dzil authordeps | cpanm
4. install module deps:
   dzil listdeps | cpanm
5. build module with dzil:
   dzil build

1. Check out module source

For my example, I'm migrating my own App::PM::Website sources from an old laptop to a new one.

Looking for example code to checkout? Try searching for dist.ini on github to find an interesting perl module. ;)

% git clone git@github.com:spazm/app-pm-website 
% cd app-pm-website

Check the code out of the repository and cd into the top level.

2. Install Dist::Zilla

On this relatively clean perl 5.12.3 install, cpanm Dist::Zilla brought in 81 packages.

% cpan Dist::Zilla
[andrew@fred]% cpanm Dist::Zilla           127 (git)-[dev] ~/src/app-pm-website--> Working on Dist::ZillaFetching http://search.cpan.org/CPAN/authors/id/R/RJ/RJBS/Dist-Zilla-4.300002.tar.gz ... OK
[... snip ...]
Building and testing Dist-Zilla-4.300002 ... OKSuccessfully installed Dist-Zilla-4.30000291 distributions installed

3. Install author dependencies

dzil authordeps will show the modules necessary for Dist::Zilla to build the module from raw source into a built module. Pipe this to cpanm to install the modules.

% dzil authordeps
Dist::Zilla::Plugin::MetaResources
Dist::Zilla::Plugin::AutoPrereqs
Dist::Zilla::Plugin::Repository
Dist::Zilla::Plugin::NextRelease
Dist::Zilla::PluginBundle::Basic
Dist::Zilla::Plugin::AutoVersion
Dist::Zilla::PluginBundle::Git
Dist::Zilla::Plugin::PkgVersion
Dist::Zilla::Plugin::MetaJSON
Dist::Zilla::Plugin::PodWeaver

% dzil authordeps | cpanm
Dist::Zilla::Plugin::MetaResources is up to date. (4.300002)
--> Working on Dist::Zilla::Plugin::Repository
[... snip ...]
Successfully installed Dist-Zilla-Plugin-PodWeaver-3.101641
11 distributions installed

4. Install module dependencies

Install the authordeps before module dependencies, in case authordeps are required for dzil to calculate the module dependencies. E.g. I needed PodWeaver installed via authordeps before I could run dzil listdeps to see the module dependencies.

% dzil listdeps
App::Cmd
App::Cmd::Command
App::Cmd::Tester
base
Config::YAML
Data::Dumper
Date::Parse
DateTime
DateTime::Format::Strptime
ExtUtils::MakeMaker
HTTP::DAV
Net::Netrc
POSIX
strict
Template
Test::Class
Test::Class::Load
Test::More
warnings

% dzil listdeps | cpanm
App::Cmd is up to date. (0.312)
base is up to date. (2.15)
--> Working on Config::YAML
[...snip...]
Successfully installed Test-Class-0.36
Test::More is up to date. (0.98)
10 distributions installed

5. Build module

dzil build will build the module into a directory and tar it up ready for cpan.

Similarly, dzil test will build the code and run the tests, you'll use this to verify your changes to the target module.

% dzil build
[DZ] beginning to build App-PM-Website
[DZ] guessing dist's main_module is lib/App/PM/Website.pm
[DZ] extracting distribution abstract from lib/App/PM/Website.pm
[DZ] writing App-PM-Website in App-PM-Website-0.112890
[DZ] building archive with Archive::Tar; install Archive::Tar::Wrapper for improved speed
[DZ] writing archive to App-PM-Website-0.112890.tar.gz

And now I can get back to the task at hand, improving this module. I'll let you know how that goes too.