AnonymousFox

//usr/share/doc/perl-HTML-Template-2.9/FAQ

FREQUENTLY ASKED QUESTIONS

In the interest of greater understanding I've started a FAQ section of
    the perldocs. Please look in here before you send me email.

1   Q: Is there a place to go to discuss HTML::Template and/or get help?

A: There's a mailing-list for discussing HTML::Template at
        html-template-users@lists.sourceforge.net. To join:

http://lists.sourceforge.net/lists/listinfo/html-template-users

If you just want to get email when new releases are available you
        can join the announcements mailing-list here:

http://lists.sourceforge.net/lists/listinfo/html-template-announce
    
    2   Q: Is there a searchable archive for the mailing-list?

A: Yes, you can find an archive of the SourceForge list here:

http://www.geocrawler.com/lists/3/SourceForge/23294/0/

For an archive of the old vm.com list, setup by Sean P. Scanlon,
        see:

http://bluedot.net/mail/archive/

3   Q: I want support for <TMPL_XXX>! How about it?

A: 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 templates.

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!

4   Q: I found a bug, can you fix it?

A: 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 has a
        publically available CVS server. See below for more information in
        the PUBLIC CVS SERVER section.

5   Q: <TMPL_VAR>s from the main template aren't working inside a
        <TMPL_LOOP>! Why?

A: 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" variables.

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.

6   Q: Why do you use /[Tt]/ instead of /t/i? It's so ugly!

A: Simple - the case-insensitive match switch is very inefficient.
        According to _Mastering_Regular_Expressions_ from O'Reilly Press,
        /[Tt]/ is faster and more space efficient than /t/i - by as much as
        double against long strings. //i essentially does a lc() on the
        string and keeps a temporary copy in memory.

When this changes, and it is in the 5.6 development series, I will
        gladly use //i. Believe me, I realize [Tt] is hideously ugly.

7   Q: How can I pre-load my templates using cache-mode and mod_perl?

A: Add something like this to your startup.pl:

use HTML::Template;
           use File::Find;

print STDERR "Pre-loading HTML Templates...\n";
           find(
                sub {
                  return unless /\.tmpl$/;
                  HTML::Template->new(
                                      filename => "$File::Find::dir/$_",
                                      cache => 1,
                                     );
                },
                '/path/to/templates',
                '/another/path/to/templates/'
              );

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.

8   Q: What characters are allowed in TMPL_* NAMEs?

A: Numbers, letters, '.', '/', '+', '-' and '_'.

9   Q: How can I execute a program from inside my template?

A: 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 seperate.

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:

<tmpl_var expr="run_program('foo.pl')">

Just, please, don't tell me about it. I'm feeling guilty enough just
        for writing HTML::Template::Expr in the first place.

10  Q: Can I get a copy of these docs in Japanese?

A: Yes you can. See Kawai Takanori's translation at:

http://member.nifty.ne.jp/hippo2000/perltips/html/template.htm

11  Q: What's the best way to create a <select> form element using
        HTML::Template?

A: There is much disagreement on this issue. My personal preference
        is to use CGI.pm's excellent popup_menu() and scrolling_list()
        functions to fill in a single <tmpl_var select_foo> variable.

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.