• Advanced level training for Perl programmers

• Turn intermediate programmers into advanced programmers

• Attempt to fill some of the many current Perl vacancies in London

• Perl is not dying

• There are currently more Perl jobs than Perl programmers in London

• London.pm jobs mailing list

  • http://london.pm.org/mailman/listinfo/jobs

• Perl community jobs board

  • http://jobs.perl.org/

• One of the largest Perl employers in London

  • http://jobs.bbc.co.uk/

• BBC Backstage

• http://backstage.bbc.co.uk/

• backstage.bbc.co.uk is the BBC's developer network to encourage innovation and support new talent.

• Various feeds and APIs

• Lots of lovely data to mashup

• Free stuff

• BBC Backstage and Yahoo!

• Hack Day 2007

• Alexandra Palace

• 16/17th June

• http://hackday.org/

• One day isn't enough time

• We'll be moving fairly fast

• Lots of pointers to other information

• Feel free to ask questions

• Use the mailing list

  • http://lists.mag-sol.com/mailman/listinfo/teachin

• 10:00 Session 1

  • CPAN

  • Templating

• 11:15 Coffee break

• 11:30 Session 2

  • ORM

  • Testing

  • Benchmarking

• 12:30 Lunch

• 13:30 Session 3

  • Object Oriented Perl

• 14:45 Coffee Break

• 15:00 Session 4

  • Various cool stuff

• 16:00 End (Pub?)

• CPAN

• Templating

• Not going to introduce CPAN to you

• Additional CPAN services

• CPANTS

• CPAN Projects

• All modules uploaded to CPAN are automatically smoke tested

• Downloaded, build and tested by over 400 testers

• Multiple platforms

• See the results at http://cpantesters.perl.org/

• CPAN Testing Service

• http://cpants.perl.org/

• Tests modules for "Kwalitee"

• It looks like quality

• It sounds like quality

• But it's not quite quality

• Number of automatically measurable criteria to rate CPAN modules

• has_readme, has_manifest, has_metayml, has_buildtool

• has_tests

• has_version, has_proper_version

• no_pod_errors

• has_test_pod, has_test_pod_coverage

• use_strict

• is_prereq

• No kwalitee criterion is a quarantee of quality

• The just tend to be seen in the same place as quality

• It's possible to "game" the system

• Produce modules that are written to raise kwalitee

  • Acme::Raise_my_kwalitee

• Ensure kwalitee is high before releasing module

  • Test::Kwalitee

• CPAN has very low entry requirements

• Not very hard to get a CPAN login

• This is generally a good thing

• Many modules doing the same thing

  • All of them subtly different

  • None of them doing exactly what you want

• Dozens of date/time modules on CPAN

• Date::Manip is almost never what you want

• Date::Calc, Date::Parse

• Class::Date

• Time::Piece

• Date::Simple

• What do you choose?

• http://datetime.perl.org/

• "The DateTime family of modules present a unified way to handle dates and times in Perl"

• "... there are several different packages with overlapping functionality, but it was hard to take dates in one package and convert them to another which you would often have to do to get a function from a different package."

• "unified" is good

• Dozens of modules that work together in a consistant fashion

• Simple case

    #!/usr/bin/perl

    use DateTime;

    my $dt = DateTime->now;
    print $dt;            # 2007-05-26T16:06:07
    print $dt->dmy, "\n"; # 2007-05-26
    print $dt->hms, "\n"; # 16:06:07

• More advanced constructor

    #!/usr/bin/perl

    use DateTime;

    my $dt = DateTime->new(year  => 2007,
                           month => 6,
                           day   => 2);
    print $dt->ymd('/'), "\n";   # 2007/06/02
    print $dt->month, "\n";      # 6
    print $dt->month_name, "\n"; # June

• A DateTime object is a point in time

• For date arithmatic you need a duration

    #!/usr/bin/perl

    use DateTime;

    my $dt = DateTime->new(year => 2007, month => 6,
                           day => 2);
    my $two_weeks = DateTime::Duration->new(weeks => 2);
    $dt += $two_weeks;
    print $dt, "\n"; # 2007-06-16T00:00:00

• Output formats with strftime

    #!/usr/bin/perl

    use DateTime;

    my $dt = DateTime->new(year => 2007, month => 6,
                           day => 2);
    print $dt->strftime('%A, %d %B %Y'), "\n";
    # Saturday, 02 June 2007

• Input format with DateTime::Format::Strptime

• DateTime::Format::HTTP

• DateTime::Format::MySQL

• DateTime::Format::Excel

• DateTime::Format::Baby (the big hand is on...)

• DateTime::Calendar::Julian

• DateTime::Calendar::Hebrew

• DateTime::Calendar::Mayan

• DateTime::Fiction::JRRTolkien::Shire

• Similar problem as with dates

• Dozens of overlapping modules

• Don't interact well

• The Perl Email Project (PEP) is a community dedicated to making Perl the best choice language for email processing. It maintains existing code, documents known problems and solutions, and develops new tools.

• http://emailproject.perl.org/

• Most people use templates to produce web pages

• Advantages are well known

• Standard look and feel (static/dynamic)

• Reusable components

• Separation of code logic from display logic

• Different skill-sets (HTML vs Perl)

• The same advantages apply to non-web areas

• Reports

• Business documents

• Configuration files

• Anywhere you produce output

• Must be easy - so many people do it

• See perlfaq4

• How can I expand variables in text strings?

•   $text = 'this has a $foo in it and a $bar';

    %user_defs = (
      foo  => 23,
      bar  => 19,
    );
    $text =~ s/\$(\w+)/$user_defs{$1}/g;

• Don't do that

• Dozens of template modules on CPAN

• Text::Template, HTML::Template, Mason, Template Toolkit

• Many, many more

• Questions to consider

  • HTML only?

  • Template language

• I choose the Template Toolkit

• http://tt2.org/

• Very powerful

• Both web and non-web

• Simple template language

• Plugins give access to much of CPAN

• Can use Perl code if you want

  • But don't do that

• Data + Template = Output

• Data + Alternative Template = Alternative Output

• Different views of the same data

• Only the template changes

  #!/usr/bin/perl

  use Template;
  use My::Object;

  my ($id, $format) = @ARGV;
  $format ||= 'html';

  my $obj = My::Object->new($id) or die;
  my $tt  = Template->new;

  $tt->process("$format.tt", { obj => $obj },
               "$id.$format")
    or die $tt->error;

• No new code required

• Just add new output template

• Perl programmer need not be involved

• Data + Template = Output

  • Template Toolkit

• Template + Output = Data

  • Template::Extract

• Data + Output = Template

  • Template::Generate

• Back in 15 minutes