[Koha-devel] feasibility of external circulation updating Koha items table availability

[Galen Charlton]

Hi,


On Fri, Feb 19, 2010 at 4:48 PM, Christopher Curry <ccurry at amphilsoc.org> wrote:
> Just to verify, I can call the itemnumber variable with:
>
> <!-- TMPL_VAR NAME="itemnumber" -->
>
> right?

Correct, although only in the TMPL_LOOP that goes through the item data.

> It seems like these variables usually use the MySQL field name, which is
> very logical.  Is that a good rule of thumb to follow when determining if a
> variable is available to a template?

It's a reasonably good rule of thumb, but not a perfect one.

> Any idea where these variables are
> defined?  I have fundamental programming knowledge, but don't know much
> about perl.  Thanks for answering the novice questions.

Koha uses HTML::Template::Pro for its templating.  Basically, an
HTML::Template::Pro object is created that binds itself to a
particular template, and variables are passed to the template via the
param() method.  get_template_and_user() in C4::Auth is a wrapper
that, among other things, creates the template object, which is
normally referred to as $template in the Perl scripts.

In the simplest case, to pass a scalar value to the template, you
would do something like this:

$template->param(bar => 'value');

In the template, that value would be retrieved using

<!-- TMPL_VAR NAME="bar" -->

You can also pass more complicated data structures.  For example:

$template->param(
  myloop => [
     { value => 'abc' },
     { value => 'def' },
  ],
);

which can be retrieved via

<!-- TMPL_LOOP NAME="myloop" -->
  <!-- TMPL_VAR NAME="value" -->
<!-- /TMPL_LOOP -->

which would emit

abc
def

Regards,

Galen
-- 
Galen Charlton
gmcharlt at gmail.com