Templates and the Templating Language¶
(Zope) Page Templates¶
Page templates (.pt files or ZPT) are an essential part of a Plone theme and are probably the easiest aspect of Plone to get to grips with. They are written in an elegant XML-based templating language called TAL, sometimes make use of macros (METAL), and sometimes incorporate Python expressions (small one-line calculations) or Python scripts.
There are several excellent introductions to ZPT, and it doesn't take long to learn TAL. Try these:
TAL is the one language that we really recommend you learn properly. The rest you can pick your way through or familiarise yourself with as you go along.
A Plone web page is delivered via an aggregation of templates, rather than just one, and there a couple of aspects of Zope Page Template that you'll need to be aware of.
A slot is a predefined section of a template. This can be left empty, or given some default content, but it is available to be filled on the fly. A slot is defined in a template in code like this:
<metal:bodytext metal:define-slot="main" tal:content="nothing"> ..... </metal:bodytext>
And filled via another template like this:
<metal:main fill-slot="main"> <h1 class="documentFirstHeading"> ...... </h1> </metal:main>
The ZPT tutorial on plone.org talks you through this in more detail, and the Templates and Components to Page section of this manual gives you an example.
2. Content view templates (_view)¶
Note: the term "view" also has a more technical application, so in the context of Components (discussed later in this manual) it will mean something different.
From the user's, contributor's, or visitor's perspective, a view is the way in which a content item is presented on the page. There's a useful introduction to this in the Plone User Manual.
Templates that are used to render a content item for a view have _view appended to their name (e.g., document_view.pt) and may have a title such as "Standard View." These templates are, in fact, sets of information ready to drop into slots.
These are small stand-alone functions for times when you need a few lines of code to perform your calculation. On the file system, they have a .py extension; you'll find them in the Zope Management Interface as Script (Python).
Here's a snippet from the event_view template (the content view for the event content type) which uses a Python script to format the a time field according to the default format for the site. If you look in CMFPlone/skins/plone_scripts, you'll find toLocalizedTime.py - just a few lines of code.
<span metal:define-slot="inside" class="explain" tal:attributes="title python:here.end()" tal:content="python:here.toLocalizedTime(here.end(), long_format=1)">End Date Time</span>