Section: User Contributed Perl Documentation (3pm)
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HTML::Template::FAQ - Frequently Asked Questions about HTML::Template
In the interest of greater understanding I've started a FAQ
the perldocs. Please look in here before you send me email.
FREQUENTLY ASKED QUESTIONS
Is there a place to go to discuss HTML::Template and/or get help?
There's a mailing-list for discussing HTML::Template at
. Join at:
If you just want to get email when new releases are available you can
join the announcements mailing-list here:
Is there a searchable archive for the mailing-list?
Yes, you can find an archive of the SourceForge list here:
I want support for <TMPL_XXX>! How about it?
Maybe. I definitely encourage people to discuss their ideas for
HTML::Template on the mailing list. Please be ready to explain to me
how the new tag fits in with HTML::Template's mission to provide a fast,
lightweight system for using HTML
NOTE: Offering to program said addition and provide it in the form of
a patch to the most recent version of HTML::Template will definitely
have a softening effect on potential opponents!
I found a bug, can you fix it?
That depends. Did you send me the VERSION
of HTML::Template, a test
script and a test template? If so, then almost certainly.
If you're feeling really adventurous, HTML::Template is publicly
available on GitHub (https://github.com/mpeters/html-template). Please
feel free to fork it and send me a pull request with any changes you have.
<TMPL_VAR>s from the main template aren't working inside a <TMPL_LOOP>! Why?
This is the intended behavior. "<TMPL_LOOP>"
introduces a separate
scope for "<TMPL_VAR>s"
much like a subroutine call in Perl
introduces a separate scope for "my"
If you want your "<TMPL_VAR>"s to be global you can set the
"global_vars" option when you call "new()". See above for documentation
of the "global_vars" "new()" option.
How can I pre-load my templates using cache-mode and mod_perl?
Add something like this to your startup.pl:
print STDERR "Pre-loading HTML Templates...\n";
return unless /\.tmpl$/;
filename => "$File::Find::dir/$_",
cache => 1,
Note that you'll need to modify the "return unless" line to specify
the extension you use for your template files - I use .tmpl, as you
can see. You'll also need to specify the path to your template files.
One potential problem: the /path/to/templates/ must be EXACTLY the
same path you use when you call "HTML::Template->new()". Otherwise
the cache won't know they're the same file and will load a new copy -
instead getting a speed increase, you'll double your memory usage.
To find out if this is happening set "cache_debug =" 1> in your
application code and look for ``CACHE MISS'' messages in the logs.
What characters are allowed in TMPL_* names?
Numbers, letters, '.', '/', '+', '-' and '_'.
How can I execute a program from inside my template?
Short answer: you can't. Longer answer: you shouldn't since this violates
the fundamental concept behind HTML::Template - that design and code
should be separate.
But, inevitably some people still want to do it. If that describes
you then you should take a look at HTML::Template::Expr. Using
HTML::Template::Expr it should be easy to write a "run_program()"
function. Then you can do awful stuff like:
Just, please, don't tell me about it. I'm feeling guilty enough just
for writing HTML::Template::Expr in the first place.
What's the best way to create a <select> form element using HTML::Template?
There is much disagreement on this issue. My personal preference is
to use CGI
.pm's excellent "popup_menu()"
functions to fill in a single "<tmpl_var select_foo>"
To some people this smacks of mixing HTML and code in a way that
they hoped HTML::Template would help them avoid. To them I'd say
that HTML is a violation of the principle of separating design from
programming. There's no clear separation between the programmatic
elements of the "<form>" tags and the layout of the "<form>" tags. You'll have to draw the line somewhere - clearly the designer
can't be entirely in charge of form creation.
It's a balancing act and you have to weigh the pros and cons on each
side. It is certainly possible to produce a "<select>" element
entirely inside the template. What you end up with is a rat's nest of
loops and conditionals. Alternately you can give up a certain amount of
flexibility in return for vastly simplifying your templates. I generally
choose the latter.
Another option is to investigate HTML::FillInForm which some have
reported success using to solve this problem.
- FREQUENTLY ASKED QUESTIONS
- Is there a place to go to discuss HTML::Template and/or get help?
- Is there a searchable archive for the mailing-list?
- I want support for <TMPL_XXX>! How about it?
- I found a bug, can you fix it?
- <TMPL_VAR>s from the main template aren't working inside a <TMPL_LOOP>! Why?
- How can I pre-load my templates using cache-mode and mod_perl?
- What characters are allowed in TMPL_* names?
- How can I execute a program from inside my template?
- What's the best way to create a <select> form element using HTML::Template?