Stories
Slash Boxes
Comments
NOTE: use Perl; is on undef hiatus. You can read content, but you can't post it. More info will be forthcoming forthcomingly.

All the Perl that's Practical to Extract and Report

use Perl Log In

Log In

[ Create a new account ]

rjbs (4671)

rjbs
  (email not shown publicly)
http://rjbs.manxome.org/
AOL IM: RicardoJBSignes (Add Buddy, Send Message)
Yahoo! ID: RicardoSignes (Add User, Send Message)

I'm a Perl coder living in Bethlehem, PA and working Philadelphia. I'm a philosopher and theologan by training, but I was shocked to learn upon my graduation that these skills don't have many associated careers. Now I write code.

Journal of rjbs (4671)

Saturday December 10, 2005
10:48 PM

my own templating engine

[ #27936 ]

It had to happen eventually, didn't it?

I guess I've written templating things before, but not many and not complicated. jGal, my lousy image gallery generator does some find-and-replace, although it inherited that from iGal. I've probably written template-like things elsewhere without thinking about it, too.

Now, though, I did it on purpose and even released it. I was tempted to call it Template::Sorry -- it's a sorry excuse for a templating system, and I'm sorry to inflict another one on the CPAN.

I'm not really sorry, though. It's different than the rest, despite being similar to a few.

I needed to write it for work, to replace an existing, similar system that wasn't quite flexible enough for what I wanted to make it do. I figured it would be pretty simple to fix in situ, but it wasn't. I thought about what I wanted, wrote some tests, wrote some code, and felt really good about it. Then I wrote some more tess, built an adapter, put it in place, watched the tests pass, and felt even better.

I deployed it to production, feeling really good about it, and within a few minutes one of my orkers asked, "Why is $SERVER swapping like crazy?"

Well, it turns out that perl 5.6.1 just really didn't like what I was doing. I was returning a closure with an enclosed closure. This seems perfectly reasonable to me, and did exactly what I wanted. Unfortunately, that seemed to leak memory very, very quickly. Just building and throwing away 100,000 empty macro expanders took up 125 megabytes of RAM in a few seconds. For long-running processes with non-empty expanders, this was not promising.

I sulked about it for a while, because I really didn't want to change my implementation, which I liked. Today I relaxed, played Disgaia, and baked and distributed some (delicious) cookies with Gloria. Then, after dinner, dessert, and some DVDs, I put together a subclass that was less elegant, but didn't leak memory on 5.6. Tests passed, memory didn't leak, and I was ecstatic.

Fixing something broken is just a really, really good feeling. I'm glad that now and again I have the chance to experience it.

Macro::Micro is on a CPAN mirror near you! (You'll want 0.03 if you're running 5.6 (and if you actually have use for the little beastie).)

The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
 Full
 Abbreviated
 Hidden
More | Login | Reply
Loading... please wait.
  • And Template Toolkit or Text::Template couldn't do this because...?
    • I wanted something to which I could feed customer-written templates with no worry of anything bad happening. Text::Template is written in Perl and TT has a much too complicated syntax. I don't want to provide IF or PROCESS or TRY. I just want "this text becomes this other text" with as little chance of real problems as I can muster.
      --
      rjbs
      • I meant to say, "Text::Template templates are written in Perl" and I don't want people running arbitrary Perl on our servers.
        --
        rjbs
      • HTML::Template (sure, it has IF, but so what?), Template::Trivial, CGI::FastTemplate, CGI::okTemplate, HTML::CTemplate, HTML::DynamicTemplate, HTML::KTemplate, Text::BasicTemplate, Text::FastTemplate, Text::QuickTemplate, Text::TagTemplate... there are more, but you get the idea. It may be that none of these was exactly the same as yours, but I bet half a dozen of them were close enough that no one else will be able to tell the difference.

        I don't want to squash people's CPAN dreams, but templating systems