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Expanded and edited the Chameleon section.

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Michael Bernstein
2014-12-07 11:43:01 -06:00
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@@ -416,27 +416,49 @@ into the corresponding block in the :file:`base.html` page.
Chameleon
---------
`Chameleon <https://chameleon.readthedocs.org/>`_ is an HTML/XML template engine for Python. It’s designed to generate the document output of a web application, typically HTML markup or XML.
`Chameleon <https://chameleon.readthedocs.org/>`_ Page Templates are an HTML/XML template
engine implementation of the `Template Attribute Language (TAL) <http://en.wikipedia.org/wiki/Template_Attribute_Language>`_,
`TAL Expression Syntax (TALES) <http://chameleon.readthedocs.org/en/latest/reference.html#expressions-tales>`_,
and `Macro Expansion TAL (Metal) <http://chameleon.readthedocs.org/en/latest/reference.html#macros-metal>` syntaxes.
The language used is page templates, originally a Zope invention, but available here as a standalone library that you can use in any script or application running Python 2.5 and up (including 3.x and pypy). It comes with a set of new features, too.
Chameleon is available for Python 2.5 and up (including 3.x and pypy), and
is commonly used by the `Pyramid Framework <http://docs.pylonsproject.org/projects/pyramid/en/latest/>`_.
The template engine compiles templates into Python byte-code and is optimized for speed. For a complex template language, the performance is very good.
Page Templates add within your document structure special element attributes
and text markup. Using a set of simple language constructs, you control the
document flow, element repetition, text replacement and translation. Because
of the attribute-based syntax, unrendered page templates are valid HTML and can
be viewed in a browser and even edited in WYSIWYG editors. This can make
round-trip collaboration with designers and prototyping in a browser easier.
The *page templates* language is used within your document structure
as special element attributes and text markup. Using a set of simple
language constructs, you control the document flow, element
repetition, text replacement and translation.
.. note:: If you've used page templates in a Zope environment previously, note that Chameleon uses Python as the default expression language (instead of *path* expressions).
The basic language (known as the *template attribute language* or TAL)
is simple enough to grasp from an example:
The basic TAL language is simple enough to grasp from an example:
.. code-block:: html
<html>
<body>
<h1>Hello, ${'world'}!</h1>
<h1>Hello, <span tal:replace="context.name">World</span>!</h1>
<table>
<tr tal:repeat="row 'apple', 'banana', 'pineapple'">
<td tal:repeat="col 'juice', 'muffin', 'pie'">
<span tal:replace="row.capitalize()" /> <span tal:replace="col" />
</td>
</tr>
</table>
</body>
</html>
The `<span tal:replace="expression" />` pattern for text insertion is common
enough that if you do not require strict validity in your unrendered templates,
you can replace it with a more terse and readable syntax that uses the pattern
`${expression}`, as follows:
.. code-block:: html
<html>
<body>
<h1>Hello, ${world}!</h1>
<table>
<tr tal:repeat="row 'apple', 'banana', 'pineapple'">
<td tal:repeat="col 'juice', 'muffin', 'pie'">
@@ -447,6 +469,10 @@ is simple enough to grasp from an example:
</body>
</html>
But keep in mind that the full `<span tal:replace="expression">Default Text</span>`
syntax allows for default content in the unrendered template.
.. rubric:: References
.. [1] `The mod_python project is now officially dead <http://blog.dscpl.com.au/2010/06/modpython-project-is-now-officially.html>`_