Including templates via parameter vs <tmpl_include>

Josh Clark <[email protected]> Fri, 21 Oct 2005 13:08:25 +0200
Newsgroups	gmane.comp.lang.perl.modules.html-template
Message-ID	<[email protected]>
Hi,

I'm curious about what method folks use to combine several templates  
into a single web page. The <tmpl_include> syntax obviously addresses  
this. But it seems tempting in some cases to create a new  
HTML::Template object for each template and include its output into a  
single "master" template as a parameter, rather than via <tmpl_include>.

I imagine this is somewhat more expensive than includes.  
Significantly so? Particularly in a CGI environment? Other downsides?

In a nutshell, it seems like this approach makes template maintenance  
easier by reducing duplication and, probably, the overall amount of  
template markup:

1) Encapsulation of parameters for reuse of templates.
For example, I'd like to create a single template that handles form  
generation. But if I want to include several forms in a page (and  
they don't stack up nicely enough to fit a <tmpl_loop> pattern), then  
I can't use the same form template via <tmpl_include> because, of  
course, the template would use the same parameters for all three  
instances. But if I generate the html beforehand via several  
different $tmpl->output calls and pass that result to a template in  
parameters, then I can reuse the same template.

2) Nesting templates to reduce duplication within templates
Generating included values via separate template objects lets me do  
something like this:
a) Create html for two forms with a single form template.
b) Include the forms as parameters to a screen/runmode template.
c) Include the html of the runmode template into a master "wrapper"  
template.

Some simple templates to illustrate that last example example...

** Master template:
     <html>
         <head>
         <title>
             <tmpl_var name="page_title">
         </title>
         </head>
         <body>
         <h1>
             <tmpl_var name="page_title">
         </h1>

         <tmpl_var name="page_content">

         </body>
     </html>
----------
** The "page_content" parameter gets generated by the appropriate  
screen/runmode template:
     <div id="column1">
         <tmpl_var name="intro_text">
         <tmpl_var name="form1">
     </div>

     <div id="column2">
         <tmpl_var name="form2">
     </div>
----------
** The "form1" and "form2" parameters get generated by the same form  
template:
     <form action="<tmpl_var name="action_url">" method="post">
         <tmpl_var name="form_title">
         <tmpl_loop name="fieldset">
             <div class="fieldset">
             <h2><tmpl_var name="category_name"></h2>
                 <tmpl_var name="category_description">

                 <tmpl_loop name="fields">
                     ... generate input fields ...
                 </tmpl_loop>

             </div>
         </tmpl_loop>
     </form>

Thanks for your thoughts and advice!
Josh



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