[NOTE: this is my summary of my interpretation of *part* of the
discussion at the views workshop at Apachecon. In other words I have
tried to represent the views of those present, but may have got some
bits wrong - this is a document for discussion not a final document.
You can get the audio from that workshop at
http://svn.apache.org/viewcvs.cgi/forrest/events/apachecon-eu-2005/workshop.ogg?rev=225666&view=log
]
What *is* a forrest:view?
-------------------------
Some of the confusion over Views seems to have come about because they
do much more than just replace skins. They add a whole new feature set.
We therefore decided to define some terminology to help clarify the
situation.
Themes
......
Currently our processing pipeline looks something like this:
src -> input plugins -> core -> skinning -> output plugins. -> out
Both skinning and output plugins are optional, so we could do any of the
following processes when working on, for example and OOo document:
OOo -> OOo plugin -> core -> skinning (html) -> HTML
or
OOo -> OOo plugin -> core -> skinning (FO) -> output plugins -> PDF
or
OOo -> OOo plugin -> core -> output plugins -> TEXT
Views currently only produce HTML and the process looks like this (at
least I think it does ;-)):
OOo -> OOo plugin -> core (views) -> HTML
We can see that forrest:views remove the skinning system. But what about
the look and feel of the page. A view does not provide that. When
forrest:views output XHTML we use CSS for the look and feel:
CSS
|
\|/
OOo -> OOo plugin -> core (views) -> HTML
=======================================================
Themes are the look and feel of a forrest output format
=======================================================
forrest:views
=============
In order to enable themes to consist of nothing more than Look and Feel
configurations there needs to be some structure to the document that
allows the theme designer to correctly apply the theme to the output
generated by Forrest. It is the job of a forrest:view to define this
structure.
But there is more to a forrest:view than just structure. Sometimes the
view also defines content that should be aggregated with the source
file. For example it may define the copyright information, a search box
or even some dynamic content, such as an RSS feed. So now we have:
theme
|
\|/
OOo -> OOo plugin -> core (views) -> HTML
| /|\
\|/ |
forrest:contracts
Here the forrest:contracts define the templated content that should be
inserted into the final document. These may create a new request in
order to generate the content, such as an RSS feed, or they may insert
statically defined content, such as a copyright notice.
Now, we need to be able to re-introduce different output formats, so the
final processing for views looks like this:
theme
|
\|/
src -> input plugin -> core (views) -> output plugin -> output
| /|\
\|/ |
forrest:contracts
View
....
Forrest:views add a structure to the generated page that
clearly identifies all the content in the final output. This is
achieved through the use of <div class="someClass"> elements. In order
to define these divs the view definition file has the concept of a hook.
this tells the view system to create a <div> element with a given class
name. For example:
<forrest:hook name="aDiv">
...
</forrest:hook>
results in
<div class="aDiv">
...
</div>
=================================================================
Hooks are only used to define the structure in our output that is
required to enable a theme to apply its look and feel.
=================================================================
The final job of views is to define where content should be placed
within the structure of the page. This is done by using a
forrest:contract. For example:
<forrest:contract name="content-title"/>
=================================================================
Contracts define templates that are used to place content in
a Forrest document.
=================================================================
NOTE: contracts may be static or dynamic. A dynamic contract will make a
further request for content whenever it is used, whereas a static
contract will always generate the same content.
View FAQs
=========
Does a view define how the page is displayed?
No. A view defines *what* is displayed. How it is displayed is defined
by the Theme.
----
What does a view define?
A view defines the structure of a document and the contracts that are to
be placed within that structure.
----
Why does a view define a document structure?
The view structure is used to allow a theme to be created independently
of the view.
----
What is a Theme?
A theme is a description of how a page is to be displayed. It describes
the look and feel of the page, but does not define any content.
----
What does a contract define?
A contract defines what content will be placed at a specific point in
the document structure described by a View.
----
What is a nugget?
A nugget is a small piece of dynamic content described by a contract.
--------------------------------------------------------------
I do hope someone will take the time to put this into the forrest:views
documentation once the content has been discussed and agreed.
