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Changes between Version 27 and Version 28 of MarkupTemplates

Timestamp:: Aug 15, 2006, 5:37:17 PM (18 years ago)
Author:: cmlenz
Comment:: Replaced section about context data with overview of Python API

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MarkupTemplates

-                      v27
+                      v28
 The most important feature provided by the Markup package is a template engine.
 Templates are XML files of some kind (such as XHTML) that include ''[wiki:MarkupTemplates#TemplateDirectives processing directives]'' (elements or attributes identified by a separate namespace) that affect how the template is rendered, and ''[wiki:MarkupTemplates#TemplateExpressions template expressions]'' that are dynamically substituted by variable data.
+Templates are XML files of some kind (such as XHTML) that include ''[MarkupTemplates#TemplateDirectives processing directives]'' (elements or attributes identified by a separate namespace) that affect how the template is rendered, and ''[MarkupTemplates#TemplateExpressions template expressions]'' that are dynamically substituted by variable data.
 This documentation is a work in progress and as of yet rather incomplete.
 …
 [[PageOutline(2-3, Table of Contents, inline)]]
+== Template Context ==
+Rendering a template boils down to applying one or more template files to some input data. This input data is represented as a [wiki:ApiDocs/MarkupTemplate#markup.template:Context Context] object in Markup. A context is basically a stack of dictionaries that manages the namespace scopes during processing: for example, some variable may be available under a given name inside a loop, but not outside of that loop.
+Regardless of its stack behavior during templating processing, a context is usually initialized from a single dictionary:
+{{{
+>>> from markup.template import Context
+>>> ctxt = Context(title='Hello, world!')
+>>> print ctxt
+[{'title': 'Hello, world!'}]
+}}}
+This data is then made available for use inside the template:
+{{{
+>>> from markup.template import Template
+>>> tmpl = Template('<h1>$title</h1>')
+>>> print tmpl.generate(ctxt)
+== Python API ==
+The Python code required for templating with Markup is generally based on the following pattern:
+ * Attain a `Template` object from a string or file object containing the template XML source. This can either be done directly, or through a `TemplateLoader` instance.
+ * Call the `generate()` method of the template, passing any data that should be made available to the template as keyword arguments.
+ * Serialize the resulting [MarkupStream stream] using its `render()` method.
+For example:
+{{{
+#!python
+from markup.template import Template
+tmpl = Template('<h1>$title</h1>')
+stream = tmpl.generate(title='Hello, world!')
+print stream.render('xhtml')
+}}}
+That code would produce the following output:
+{{{
+#!xml
 <h1>Hello, world!</h1>
 }}}
 Here the `title` variable in the context is accessed through a ''template expression'', discussed below.
+See the [ApiDocs API docs] of the [ApiDocs/MarkupTemplate markup.template] and [ApiDocs/MarkupCore markup.core] modules for more details.
 == Template Expressions ==
 …
 }}}
 The rationale behind the second form is that directives do not always map naturally to elements in the template. In such cases, the [wiki:MarkupTemplates#pystrip py:strip] directive can be used to strip off the unwanted element, or the directive can simply be used as an element.
+The rationale behind the second form is that directives do not always map naturally to elements in the template. In such cases, the [MarkupTemplates#py:strip py:strip] directive can be used to strip off the unwanted element, or the directive can simply be used as an element.
 === `py:content` ===
 …
 {{{
+#!xml
 <html xmlns="http://www.w3.org/1999/xhtml"
       xmlns:py="http://markup.edgewall.org/"
 …
 Include paths are relative to the filename of the template currently being processed. So if the example above was in the file "`myapp/index.html`" (relative to the template search path), the XInclude processor would look for the included file at "`myapp/base.html`". You can also use Unix-style relative paths, for example "`../base.html`" to look in the parent directory.
 Any content included this way is inserted into the generated output instead of the `<xi:include>` element. The included template sees the same [wiki:MarkupTemplates#TemplateContext context data]. [wiki:MarkupTemplates#py:match Match templates] and [wiki:MarkupTemplates#py:def template functions] in the included template are also available to the including template after the point it was included.
+Any content included this way is inserted into the generated output instead of the `<xi:include>` element. The included template sees the same context data. [wiki:MarkupTemplates#py:match Match templates] and [wiki:MarkupTemplates#py:def template functions] in the included template are also available to the including template after the point it was included.
 By default, an error will be raised if an included file is not found. If that's not what you want, you can specify fallback content that should be used if the include fails. For example, to to make the include above fail silently, you'd write:
 {{{
+#!xml
   <xi:include href="base.html"><xi:fallback /></xi:include>
 }}}
 See the [http://www.w3.org/TR/xinclude/ XInclude specification] for more about fallback content. Note though that Markup currently only supports a small subset of XInclude.
+Incudes in Markup are fully dynamic: Just like normal attributes, the `href` attribute accepts [MarkupTemplates#TemplateExpressions expressions], and [MarkupTemplates#TemplateDirectives template directives] can be used on the `<xi:include />` element just as on any other element, meaning you can do things like conditional includes:
+{{{
+#!xml
+  <xi:include href="${name}.html" py:if="not in_popup"
+              py:for="name in ('foo', 'bar', 'baz')" />
+}}}
+----
+See also: MarkupGuide, MarkupRecipes