• How to write a simple database-backed website with Perl modules Mason and Class::DBI

    Alfie John over at rental-property.co.nz wrote to tell that the source code for the entire site, written using Mason and Class::DBI, is available for download.

    For someone wanting to see an overview of how either Mason or Class::DBI work with real-world examples, not just samples from documentation, this is a great place to start.

  • Ian Hague funds Perl 6 development through the Perl Foundation

    Just announced on the TPF news site, a huge donation to TPF to fund Perl 6 development:

    On May 14, 2008, The Perl Foundation received a philanthropic donation of US$200,000 from Ian Hague. Mr. Hague is a co-founder of Firebird Management LLC, a financial fund management company based in New York City. This donation was the result of extensive discussions between Mr. Hague, The Perl Foundation and a Perl community member who wishes to remain anonymous.

    The purpose of the donation is to support the development of Perl 6, the next generation of the Perl programming language. Roughly half of the funds will be used to support Perl 6 developers through grants and other means. The balance of the funds will be used by The Perl Foundation to develop its own organizational capabilities. This will allow The Perl Foundation to pursue additional funding opportunities to support Perl 6 development. Mr. Hague wants his contribution to be seed funding in that effort.

    The Perl Foundation thanks Mr. Hague in the deepest possible terms. This donation is unprecedented in its generosity, scope and vision, and it is precisely what was needed at this junction in the development of Perl 6. We look forward to the greatest of successes with Perl 6, and this contribution is a key part of making that happen. The Perl Foundation will communicate further developments with the Perl community and Mr. Hague as the pieces of this plan are executed.

    Thank you to Mr. Hague for supporting Perl 6's continued development.

  • Optimizing file searches with File::Find::Rule

    Adam Kennedy posted an excellent article about huge performance hits he found with File::Find::Rule. From the docs, there's this sample to find all the *.pm files in @INC:

    # Find all the .pm files in @INC
    my @files = File::Find::Rule->file
    ->name( '*.pm' )
    ->in( @INC );

    What this search REALLY says is "Find every single file in all these trees, then do an slow IO stat call to the operating system on every single one to work out which ones are files, and only then do a quick regex match on the file names to keep the 5% that have the ending we want and throw away the 95% that don't".

    Now I'm worried about if I'm doing the right order of checking in File::Next, a lightweight file finder that ack relies on.

  • Colons invalidate BEGIN and END blocks

    Take a look at this block of code and see if you can guess what it does.

    END: {
    print "Exiting...n";
    print "s = $sn";
    BEGIN: {
    $s = 'Hello from the BEGIN phase';

    You'd expect that the BEGIN block sets $s at compile time, so then that gets printed in the print statement, and then the END block executes at the end of the program. Yes, it would, except that those aren't BEGIN & END blocks. They're normal blocks that just happen to be named BEGIN and END.

    Credit Randy Lauen for bringing this to my attention. Today at my day job he found a horrifying code construct, one that I'd been using (incorrectly) for quite some time now. You see, these two blocks are not the same:

    BEGIN {
    # Here's some code that gets executed at compile time
    BEGIN: {
    # This code gets executed at run time, because the colon
    # after BEGIN means it's just a plain old label

    Randy had been tracking down a bug for over an hour and couldn't figure out why his variables weren't getting set at compile time. Turns out the BEGIN block he was modifying was actually a not-special-at-all BEGIN: block. And he found 40+ instances of the spurious colon in the codebase. Of course, INIT, CHECK, UNITCHECK and END are also rendered non-special by a colon as well.

    Most of the time, this is invisible. People tend to put their BEGIN blocks at the top of the program, so the difference between a real BEGIN block and a block that happens to be named BEGIN are not noticed. Still, it's a a bug waiting to happen. Sounds like an ideal check for Perl::Critic policy, no? Mike O'Regan jumped to it, and submitted a patch to Perl::Critic, so those of you using Perl::Critic (and if you're not, you should be) can get warned of using colons on those specially-named blocks once a new version is released, shortly I hope.

    I'm not the only one to have been doing this. Google Code Search turns up over 100 instances, including some in the core Perl tests (heck, maybe from me!), as well as mailman and POE.

    Check your codebases. If you're using ack, it's just:

    $ ack --perl '^(BEGIN|END|INIT|CHECK|UNITCHECK):s*{'

    Have you fallen prey to this? Let me know.

  • Perl must decentralize, diversify and colonize

    Perl's big problem is one of perception. The other day, a job candidate asked me "You're moving your web apps from PHP to Perl? Shouldn't it be the other way around?" Why did he think that? The candidate knew no Perl, and only a bit of PHP, so had no technical reason to believe that PHP was better than Perl. So why did he think Perl was subservient to PHP in the web arena?

    What I suspect is that Perl is just less visible, and not just in the sense of crap like the TIOBE index where it equates hits for "Foo programming" popularity of the Foo language.  I'm talking about in the real way people see the world of programming.

    I'm certain that PHP has become a de facto choice for basic web apps because it's just How You Do It these days. You see enough PHP in the context of the web, it starts to sink in.

    Why is Ruby on Rails so popular? Is it better than Perl on Catalyst? Or is it just that people hear about Rails more? I suspect the latter, because perception is reality. When people perceive Perl as being dead, or not as powerful as other tools, it might as well be.

    There are three goals I'd like to address:

    • Perl needs diversity, needs new blood, both in users and community as well as tools.
    • Perl needs more active mindshare in the programming world.
    • Perl 5 must continue to be seen as a viable language.

    The three actions to take: Decentralize, diversify and colonize.

    Perl must decentralize

    Perl has a great infrastructure. We have the CPAN. We have the various sites of perl.org. We have Perl Mongers and perlmonks, and so on. Unfortunately, we've grown complacent. It's time to start looking elsewhere for infrastructure and community.

    Standardization on tools makes sense if the tools are the best possible tools available. In many cases, the infrastructure already in place in the Perl community may not be the best there is.

    Is the Mailman installation running on lists.perl.org the best mailing list solution for you when you need to start a mailing list? If not, then consider other options. Starting a list at groups.google.com is trivial, for example.

    Is rt.cpan.org the best bug tracking solution for your modules or projects? If not, then look at other options. Many of my modules, such as ack and WWW::Mechanize are hosted at Google Code, where I use the bug tracking system there.

    Is use.perl.org the best place to host your blog? Maybe you should post somewhere else. Certainly that was the case with me. I found that use.perl.org wasn't the news site I wanted it to be, so I started Perlbuzz as an alternative, literally doubling the number of news sites devoted to Perl.

    Note that "alternative" does not me "replacement". It's possible to have two similar but diferent projects, websites or whatever that both fill a need. If, say, Perlbuzz replaced use.perl.org, we'd still only have one news site, which is no better a situation than we started with.

    Some of the alternatives might not be community-based. Google Code, is not run by altruistic volunteers. Commercial interests will usually have more time and money to spend on providing useful infrastructure. That's no knock on the volunteers, but merely taking advantage of what the commercial interest has to offer.

    (I know at some point someone will say "At some point decentralization is harmful." I agree, but we're nowhere near that point. Such a problem to have!)

    Perl must diversify

    The mantra "There's more than one way to do it" is at the core of Perl the language, but this is not always the case in the Perl community. We must always remember the guiding principle of TMTOWTDI.

    The first place to diversify is with people. I suspect, but cannot prove, that the Perl community's size is a net loss as time goes by. We must constantly be trying to bring new people into the fold, to take advantage of their innovations, and to make what we do more fun.

    Second, we must be willing to launch new projects, even if they're similar to existing projects. It could be a module, or a website, or an entire application. The knee-jerk resistance to diversity often sounds like this:

    • "Why do we need Getopt::Whatever, we already have Getopt::Long"
    • "Why do we need another templating system?"
    • "Why do we need Jifty/Catalyst/whatever? We already have Maypole."
    • "Why do we need Perlbuzz, we already have use.perl.org?"

    I've never understood this fear. It sounds like the resistance is based on the premise of "I wouldn't want to do that project, so you shouldn't either." It's the refrain of someone with a closed mind, unable or unwilling to imagine what could be. In the case of similar modules, the refrain usually goes "It's too hard to find the module you want anyway," but that's not a problem of the module, but of the way things are found in CPAN itself. (And if you'd like to address that little bit of decentralization, please take a look at my Rethinking CPAN mailing list.)

    Ultimately, fear of the new is counter to the principle of TMTOWTDI. Indeed, plurality is at the very heart of open source, and it's additive, not subtractive. Template Toolkit need not take away from Mason. Perlbuzz need not take away from use.perl.org. Perl didn't take away from awk and shell. In any of these cases, if the new solution does take away from another, then the other solution was an inferior one to begin with.

    Decentralizing and diversifying do two things. First, it opens our minds to alternatives that we may not have considered. It makes us more likely to find solutions that are better than what we started with. Second, it helps with colonization, the ultimate goal.

    Perl must colonize

    The other day, Tim O'Reilly posted on his Twitter feed a link to a cool article about life in the universe which mentioned Von Neumann probes, theoretical space craft that can replicate themselves using materials found in their travels. A single probe could travel some distance, replicate a thousand cloned probes, which would then launch in a thousand different directions, repeating the cycle.

    That's what we need to do: Colonize the mindshare of the world to let them know that Perl is still viable, and a hell of a lot of fun. These new Perl lovers will spread the love as well, and the cycle will continue. In terms of action, it means simply "helping make more people aware of Perl as a cool & useful language." Fortunately, it's a case where we can think globally and act locally, even passively.

    The biggest effect I see you, the reader, as being able to have is by spreading out Perl's web footprint. I want more places for people to find out about Perl, rather than a few big ones.

    This colonization approach goes hand-in-hand with decentralization. Take my ack project, for example. ack has a number of footprints out there:

    That's three times places for people to stumble across Perl, to see it mentioned. A separate home page also makes it more likely to get linked from somewhere else, as when Daring Fireball linked to ack and thousands of people came to see about ack. That's thousands of people who went and saw "Huh, here's a tool in Perl."

    Of course, a few thousand visitors isn't going to change any mindshare. That's why it's not just me that needs to work on this. Fortunately, decentralizing and diversifying makes colonization easy.

    Our Google footprint is pretty bad, anyway. When I search for "perl" in Google, the top five hits are:

    • perl.org, which is a good base.
    • perl.com, O'Reilly's Perl page, also a good base.
    • The wikipedia entry for Perl, which certainly isn't much help for a beginner
    • www.cpan.org, with its front page that expects that you know what you want.
    • An old perl 4 man page from Carnegie-Mellon University

    Is this the best impression that we have to give the world?

    Adam Kennedy gets it

    Adam Kennedy's Strawberry Perl is a marvel of the principles I've talked about. Strawberry decentralizes, as it uses none of the core perl.org infrastructure, and it diversifies and colonizes by giving Windows users an alternative to ActivePerl, which for many users is not robust enough. When people talk about Strawberry Perl, it helps with mindshare as well.

    Adam is a great example of someone who has set out to make improvements to a part of Perl, and implemented it without worrying about permission or duplication, helping Perl as a whole along the way. I thank him for it. I suspect his Perl On a Stick project will have similar results.

    How you can help?

    The strategy of decentralize/diversify/colonize takes actions at all different levels. You don't have to go create your own Perl distribution, or even write any code. Here are some other ideas to get you started.

    • Post a Perl-related web page to Digg, reddit or any of the other social bookmarking websites.
    • Bring someone new to a Perl Mongers meeting, even if Perl isn't his/her primary language. Especially if it isn't his/her primary language.
    • Go to a user group meeting for another language. See what they're talking about. Share the Perl perspective.
    • Start a blog outside of the use.perl.org hierarchy. If you already have a u.p.o journal, keep it, and post to both places.
    • Start a mailing list related to a project of yours. Host it somewhere like Google Groups. Don't worry that "people won't be able to find it," because the list of groups at lists.perl.org is no model of organization, either. Besides, the only people who know to look at lists.perl.org are the people that already know there are lists at lists.perl.org. They're not who we're after.
    • Start an alternative to perlmonks.org. Perlmonks is a fine site, but it's long in the tooth, daunting to newbies, and frustrating to search. Surely there's a different way to have an online Perl forum that is better in many cases.
    • Work on a project that helps cross-pollinate Perl to the rest of the world. The Test Anything Protocol is a good example of this.
    • Review a book about Perl. Get it posted to Slashdot or another big tech site.
    • Write about Perl in your blog. Even if you think it's not interesting to Perl people, that's fine. Someone will want to read it, and you'll spread that mindshare.
    • When you talk about Perl, don't be afraid to use the F-word and the L-word: "fun" and "love".

    What do you think?

    I'd like to hear your ideas. How can we expand Perl's reach? What have you done to help decentralize, diversify and colonize? How can we keep Perl fun and exciting?

    Two comments I don't need to hear: "This will never work" and "This is a waste of time." If that's what you have to contribute, trust that I've taken your insight into account already, and save yourself some typing. Alternative courses of action, however, are more than welcome. Also unnecessary: "None of this would be a problem if not for Perl 6."


    Thanks to a number of people who have helped discuss these ideas with me as I put them together. These include Pete Krawczyk, Jeffrey Thalhammer, Ricard Signes, Liz Cortell, David Hand, Jesse Vincent and Elliot Shank. I'm sure I've forgotten some, so I apologize if I left you off the list.